Noobie Question: What to worry about with my 370z 7AT upgrades?

[kinitox]

Hi,

This is my first post here even I have a lot of time in this forum. right to the point, I have a 2009 7AT NA 370Z which I use for Daily drive, spirit drive in highways (of course safety) and like to go to Drag some times (13.5 Secs all stock), I live in the Caribbean so high temps mostly 36 to 40 C. now I will update Z with the following mods:

1- G3 Stillen Intakes with dry filters.
2- AT Cooler from Stillen
3- 34 row Oil Cooler from Z1 Motorsports
4- Stillen Lightweight underdrive pulley
5- Nismo Exaust
6- ART Pipes by Motordyne
7- Uprev tunner Kit
8- New OEM Spark Plugs
9- New Nismo Oil Filter

At this point my car has a littler bit more than 61K Miles so here comes my questions:

1- Based on this configuration, what kind of advice can you give or worry about these mods?
2- Even I read a lot of Stillen Pulley, I still not clear if it will hurt my Engine or not based on my config.?
3- Do i need to change the timing belt? can any one recomends me all i need to buy (timing change, tensor, ??)?
4-Also do the new Tranny oil cooler, i will flush the actual oil and apply a new one, specific the Motul ATF VI. It this is OK or do i need to doit in another way?
5- as I will use Uprev to take the best perfom of my mods, any advise or something do I should consider in terms of security or tell my tuner to watch out?
6-Based on what i read in this forum, Should i expect around 50HP more in my car without hurting nothing, maybe be in the high 12 Secs in drag?
7- Anything that i might missing?

I will really appreciate your comments because I will start to work the car during next week.

Thanks!