I just attempted to put in my Fast Intention HFCs this past Saturday, I had everything going well until we tried to attack the demon bolts, we ultimately couldnt get it, but Im gonna give it another go this week.

We gave it a go about a week later, we ended up cutting the passenger side OEM cat off, and we got extremely luck on the driver's side, as the bolt snapped off. *HUGE* sigh of relief.

Now Im just working on clearing the CEL/SES codes, as during the process, we ended up messing up the passenger side o2 sensor on the exhaust manifold. :facepalm:

I'm going to finally throw my ART pipes on later this week using this DIY. I had HFC put on previously when my exhaust was installed so I wont have to deal with the demon bolts. Now I need to raid the hardware store for some extensions.

Excellent write-up. Did this install today with a pair of Stillen HFCs and everything went nice and smooth (minus a couple hour battle with the dreaded evil bolts on the upper flange). Thanks for the info here. +1 rep from me. :tup:

How worried should I be about breaking the O2 sensor? Gonna be installing ART pipes in a few weeks and I'd hate to have to spend hundreds of bucks more if I break them.

You should definitely be able to do this install without breaking the 02 snesor dude. with the proper wrench..if you don't have one..buy one from advance auto, use it, then return it the next day haha.

excellent write up. I chose to have them installed by a nissan tech but this write up is SPOT ON from what I've researched over the last few months.

i wouldn't be worried

Just dont use any impact tools.:tup:

Excellent write up. I must admit I was a little concerned at first with how tough the Demon bolts were going to be, but everything went pretty smooth. I was installing Motordyne ART pipes coupled with a Berk CBE. I started out by running the car for about 5 min. and then spraying down all of the bolts with Kroil, starting with the demon bolts. From there I started breaking loose all the bolts from the cats back allowing soaking time for the demon bolts. Used open end wrench for O2 sensor. No need for O2 socket. Using a long handled 1/2 wratchet with impact sockets made this job a lot easier. When it came to the demon bolts I used a 24" impact extension, 12" impact extension and swivel socket. Used the handle from my floor jack as my breaker bar and the dreaded demon bolts were a piece of cake. No broken or snapped tools. :tup:

Special thanks to Fred Beans Nissan for great pricing, Tony at Motordyne and my 8 yr old son who stayed up until midnight (way past his bedtime) to help me. He couldn't wait to go for a late night test drive :happydance:

Man, thats awesome.

I used this guide to install my Berk HFCs earlier this year and it was a great help. I sprayed down the bolts with WD-40, went out to eat lunch with buddy in his STi, came back and sprayed it down again. Ran into 2 demon bolts (1 each). We ended up snapping the bolts at the midpoint but at least it came off.

Just remember not to rush the process. Be patient as much as you can because it will only get worse if you're not. Make sure the wrench and socket are flush with the bolt and not at angle before you apply pressure to loosen the bolt. It's tough to do this since the engine is in the way lol. My friend would lower the extended wrench down and I would go under the car and guide the socket onto the bolt to make it's flush before he starts to apply pressure. Just my 2 cents. Good luck everyone. Be PATIENT!

Installed my Berk HFC yesterday in my garage with the Z up on ramps and jack stands. It took about 6 hours, but I took my time... PB blaster soak, lunch and the demon bolt. The passenger side demon stripped but using a bolt extractor saved me. Some people had questions about the bottom 2 of the 3 bolts going to the headers. They look tough to get to at first but you can access them from below, the wheel well to the side and you can fish a wrench past the bolts and come down from the top (this is handy installing the new bolts because you need to hold the opposing nut/bolt as they both want to turn as opposed to the stock studs. The offset on some box wrenches just get you there.
The only problem I had that wasn't mentioned here was that Berk tossed in a standard/course thread bolt in the bag... I snugged down that one bolt and went to release the wrench holding the other side and noticed the bolt was very loose. Backed it out and looked at it and sure enough, the nut would only go on 2/3 of the length of the nut because of the wrong thread. I just replaced it with another. No knock on Berk because the quality of the cats... Weld and fit are excellent. The nuts and bolt guy was just having a bad day. Oh, final thought, I received both sets of gaskets (front and back). I have seen other post saying only front or pictures showing only front. Happy with the results.

Now that's what I call going bat$hit crazy with an uncooperative car part. My friend, you rock!

What about applying anti sieze goop in the event you need to remove stuff down the road?
Recommended or not necessary?

This help thanks just use a 1/2 ratchet better.