I bought a 1991 Isuzu Impulse RS (1.6 turbo/awd) to enter into Auto-X events and as my first official project car. It is running ok, and needs some bodywork. I found some info after digging thru this section on TR. I know it will be in G-Stock and this was the rules for it.

Stock
As a rough guide, if your car has modifications beyond this list it is not eligible for Stock Category:
* Anything available on the exact model and year of your car as standard or optional equipment, as installed on the factory assembly line (nothing available only dealer-installed is allowed), plus
* Standard OEM identical replacement parts
* Accessories, gauges, appearance, comfort, and convenience items (not replacement driver's seat, though) that basically don't help
* Added roll bar or roll cage to spec (not required, though)
* Driver harness (no cutting seats to install, though)
* Trailer hitch and/or tow bar mountings
* Any wheel of diameter and width identical to a stock or factory optional wheel, offset within +- 0.25 inch
* Most street legal tires that will fit the mounted wheels and stock bodywork
* Any shock absorber of the same type and mounting as original; no change to standard spring mountings is allowed; suspension geometry may not be altered; gas or hydraulic shocks are permitted
* Any brake linings; pre-1992 cars may use solid/braided metal brake lines.
* Any front anti-roll bar (no change to stock/optional rear anti-roll bar, if present)
* Manufacturer specified ignition settings only
* Any replacement air filter element (or removal of air filter element); no plumbing changes, however
* Engine bored no more than .020"; no balancing or porting/polishing of head
* Replacement of any part of the exhaust system past the catalytic converter (if quiet)
* Any oil filter
* Added clutch scattershield

I plan to get for the car. New Rims/Tires matching OEM size. A full tune up using good parts. Some gauges for the boost, oil and air/fuel. A boost controller. K&N air filter in stock box. New rotors and brake pads (may use upgraded lines since car is a 1991, also is cross drilled or slotted allowed???). 2.5" exhaust from the cat back (is gutted cat allowed??) For the muffler I saw a flatblack stock looking muffler with 2.5 inlet (not sure about exhaust rules). Plan to get the bodywork fixed and new paint. May get some decals of a website that Im working on installed and some minor stickers and stuff. Is the CG lock for the seatbelts allowed? Plan to get KYB shocks to replace the oem, but use oem springs (is this ok?).

Any help is appreciated on what I can do to remain in G-Stock for awhile. I plan to upgrade the rest of the car as I become a better driver. Also its March already, how does SCCA work.. is there a season or I just come to the events Im interested in and skip others. --- Thanks