I race with the SCCA and just about anything modded will kick you out of stock class with a few exceptions. Pretty much the only performance items that can be upgraded are:

- Tires (must fit on stock rims) - By far the largest improvement
- Alignment
- Brake pads
- Front sway bar
- Shocks
- Exhaust (only good for saving weight I hear)
- Remove spare tire and tools

You're right the book is giant. I took the short cut and just talked with my local rep, very nice guy. Pressure plate is ok to update as you get no performance improvement, but the lightweight flywheel kicks me out of class from the reduced weight.