My diff is from a 6MT, and there is the exterior flange that bolts up to the drive shaft that's different, but swappable.

http://i451.photobucket.com/albums/q...ps92f14071.jpg

Review 4.08 Ring & Pinion Swap, she's alive! - MyG37

Here's a compiled list for VLSD drop ins:
List of aftermarket LSD for VLSD cars - MY350Z.COM Forums

For the wavetrac, looks like you need an open stud and a different stud (which might work with one side of the vlsd stud)
nasaforums.com • View topic - Wazvetrac issues/discussion

So, to sum up the (perhaps obvious to some!) things I've confirmed from looking at gears lately:

Given the shape of all VQ horsepower graphs, the things that really matter in the end, once you've seen the data, is "How do the gear gaps relate to each other" and "what's my max speed in top gear". As long as the gear gaps get shorter as you go higher in the box, and you don't run out of top speed, you're winning by going to a lower rear end ratio in terms of area-under-the-curve on the HP-vs-Speed graph (subtleties about shift points/delays notwithstanding).

In both the 6MT case and the 7AT case (ignoring the useless 1st gear, anyways), the gaps do get smaller all the way up the gearbox. While both exhibit the same basic narrowing of the gap as you go higher, the 7AT has significantly wider gears at the bottom and narrower at the top, vs the relatively-stable profile of the 6MT's gears, meaning there's probably less advantage to extreme gearing in the 6MT (but it's still there).

The percentage change in gearing per upshift looks like this:

7AT: 35.1% -> 36.0% -> 30.9% -> 29.2% -> 13.8% -> 10.4%
6MT: 38.7% -> 30.1% -> 21.7% -> 21.3% -> 20.6%

Top speeds in top gear with various rear ends discussed above, assuming 275/35R18 and a 7500rpm redline:

7AT:
3.357 -> 220
3.692 -> 200
3.917 -> 188
4.083 -> 180
4.364 -> 169
4.636 -> 159
4.900 -> 150

6MT:
3.357 -> 214
3.692 -> 194
3.917 -> 183
4.083 -> 175
4.364 -> 164
4.636 -> 154
4.900 -> 146

Some of those things change between the G37/370/350. I'm pretty sure both 6MT and 7AT 370Z rear ends have the same input flange on the driveshaft side. And no matter what pumpkin I'm using, I need at least one axle-shaft if I'm switching from VLSD to aftermarket LSD (but not open to aftermarket LSD). But for some reason other than those issues, there's a difference between the 7AT and 6MT 370 rear ends (enough that LSD mfgs generally are 6MT-compatible only, or make a separate model for 7ATs). It's either that the much-higher ratio in the 7AT is actually a different diameter (in which case I don't care, that gear set is being tossed anyways), or it's that the inside of the pumpkin has an odd shape for some reason I can't fathom. In any case, though, it seems the common solution others have employed is to grab a used 6MT pumpkin and slap it into their 7AT car. I think the 350Z and G37 6MT pumpkins both work in that case. Anyways, I really don't know, something to research later in the week :)

My rain tires arrived! These are the discontinued Continental-brand "Wet Radial Race Tires" that Hoosier's selling for $100/tire in 265/645R18 (if you order these, be sure to note there's a Left and a Right, get two of each!):

https://lh3.googleusercontent.com/5F...I=w506-h851-no

https://lh4.googleusercontent.com/ff...c=w900-h851-no

Now the interminable wait for the wheels to mount them on. I can't wait to see how these feel in the rain.

I just bought 5 sets of the continental 285/645 slicks!

Nice!

Any idea how the 285/645 slicks compare to DOT tire sizes? I've heard that the slick sizes vary quite a bit from what one sometimes expects, sometimes wider? I'm *hoping* my 265/645 wets will fit well on 10's, but I wasn't sure enough to bet on the 285 slicks yet until I see how this looks.

Those look wide for 265.

Yeah. Both my RS3's and Conti DW's are 275/35 on 18x10. When I compare the unmounted 265/645's to the mounted DW's (just lining them up with each other on the floor), the width looks identical. But we'll see what happens when they're mounted. If they do fit, and the sizing is consistent between dry+wet, that makes me think 285/645 might be a tad wide for 10's, but I have no idea. I guess the smart thing to do would be to call Hoosier and ask :)

I didn't find time to call Hoosier, but I did find rim sizing elsewhere on their site for new Hoosier slicks, which is probably identical to this stuff (the Conti is just branding, I think Conti actually owns Hoosier and Hoosier makes all slicks with Conti written on the side?).

In any case, in "recommended rim width" for new Hoosier dry slicks, 265/645R18 is 9-10 and 285/645R18 is 10-12. So they probably work on 10's, maybe a little fat-looking :)

I run 295/40 Hoosiers on my 9.5s and my 10s, so I plan on the same with these.

On the sizing, the 645 is the total tire height, 25.4", which would make the 265s roughly a 35 and the 285s roughly a 32 in common aspect ratios.

I have those same wets too. They wouldn't fit on my 18x8s, but I do have them mounted on a set of 18x9s, so 10s will work fine

Well, I wasn't planning on buying any dry slicks until at least after I burn through this set of RS3's, but now I'm kinda tempted to stock up on some of those 285's while I can and just store them in the house for a few months :)

exactly. one set is just a fraction more than 1 regular priced hoosier.

I was reading up on the compounds and whatnot, those 285/645's are "GT-O", which is supposedly slower rubber than an R6, FYI (whereas their "GT-R" compound is faster, but no discontinued ones of that in the right size). Apparently GT-O was a special compound they did for the high banked oval courses like Daytona. But still, it's cheap, and it's not like I really care about my lap times. My first set of slicks is just going to be about learning whether I can handle driving on slicks or not :)

Signed up for a NASA membership! Tentatively, I think my main schedule for TDE+NASA for the rest of the year looks something like:

Apr 5-6: MSR-Houston - The Driver's Edge
Apr 26-27: Nismo Fiesta @ H2R
May 17-18: TWS - The Driver's Edge
June 21-22: Hallet - NASA
Aug 9-10: TWS - The Driver's Edge
Sep 6-7: TWS - The Driver's Edge
Sep 20-21: NOLA - NASA
Oct 4-5: MSR-Houston - The Driver's Edge
Oct 11-12: TWS - NASA
Nov 1-2: Eagle's Canyon - NASA
Nov 22-23: TWS - The Driver's Edge

I've only signed up for the first three so far. The rest are of course pending work conflicts and such as we get through the year. I'll probably ending up dropping one or two of those events, and I'll probably try to squeeze in a few more TWS visits that don't require as much notice where I can (PDS, PCA).

Hallet's going to be a crazy-long trip for my first NASA event (~8hr drive each way). I had planned to start doing MSR-Cresson w/ TDE this year, which I'm not anymore. I really want to get into NASA's system this year and start working my way up to TT + Comp School there. So I figure that means squeezing in the only 4 NASA events I can reasonably hit this year, which means learning 4 other new tracks for the first time (H2R for NismoFiesta, + NASA @ Hallet, NOLA, ECR). I don't need a 5th new track all in this hectic year (I think I still get better skills-building out of working on known tracks at this point), so Cresson will have to wait for later!