From what I've been able to determine, all G37s are in the FS class (muscle cars) as long as they are on street tires.

If I install a strut tower brace, will that affect the classification?

 

Better check the rulings on that. There are very few things you can do before it kicks you up a class. I am running a cat back and thats about all you can change with out going up. I don't know about the tower brace but you really can't do anything to the suspension before you go up. Most local SCCA clubs have a forum where you can get the answers to these questions. I am sure there are ones there in NY that can help you out on this.

 

OP if you add any aftermarket parts (aside from tires), you'll get bumped from the stock class. Only thing you're allowed switch up are tires when in stock. Don't ask why.

Tazicon, you're not in stock class are you? You're probably in street touring at which you would need a considerable amount of mods before going into the street mod category.

 

Yep I am in the stock class. As long as you don't touch the cats you can stay in the stock class.

 

I have a full suspension done and I race in the E Street Prepared "ESP". I go up against camaro's, mustang's, GTO's and firebirds. So far "knock on wood" I have beaten them all. My exhaust is still stock and the only engine mod is a intake.

 

I ran my G37S in FS at the last event but had someone come up to me and tell me that I should be in DS that G37 and G35's got moved this year. I've found nothing to back this up though.

 

I did some more searching and found this:
STOCK
- The following classing change proposal is published here for member comment:


- Move from DS to FS: Ford Mustang V6 (2012) Comment: this move is linked to the published proposal to move a variety of other cars to DS from either GS or FS. The desired result is that the ’11 Mustang V6 and those other cars (Genesis V6, G35 coupe, Infiniti G37 coupe, ’10-’11 Camaro V6, ’10-’11 Challenger V6) will be classed together in DS or not moved from their current classes.




here:
http://www.scca.com/documents/Fastra...-june-solo.pdf

But that was 2011. I then found the actual 2012 rulebook:
http://www.scca.com/assets/2012_Solo...ry_reduced.pdf

All G35s and G37 coupes are now DS, but G37 sedans are still in FS.

 

I have been autocrossing my Z for ~7 years and have only really kept up with where my car gets classed. However, I may be able to help with some of the general questions.

The stock classes do allow for some mods.

The mod that makes the most difference other than the driver is the tires. A set of race tires will make a bone-stock car faster than an FI car on showroom stock street tires. (with the same driver)

For some reason, race tires are allowed in the stock classes and have been for a very long time.

The shocks can be swapped out for adjustable aftermarket shocks and the front sway bar can also be changed. (I heard they were talking about allowing the rear bars to be changed too, but never saw anything official on it.)

You can get lightweight aftermarket wheels, but they have to be the same width and diameter as stock, and close to stock offsets. (I don't remember the max offset difference allowed from stock, but it's not much from what I remember)

Cat back exhausts are legal.

I thought springs could be swapped if they didn't alter ride height, but I heard that years ago and have not checked on it lately.

I don't think an aftermarket strut brace is legal, but I'm not 100% sure.

While race tires make the biggest bolt-on difference by a large margin, it's generally recommended that people get comfortable/consistent with street tires first and then move up to race tires if they so choose.

Race tires have a way of covering up mistakes where street tires tend to make mistakes obvious.