Ok.... Fist thing in a car built to class is the Preperation rules
IP Uses the SCCA IT Rules for Car Prep
CACC Has some allowances to those rules Example Brakes ,,,Weight,,
Thats in the CACC Race Regs
You Coil ajust the spring,Ibach springs in any poundage you desire, and put in performance shocks,in there location,
Here is the Rule on Springs and shocks
b. Springs and Shock Absorbers
1. Shock absorbers may be replaced provided that the
replacements (a) attach to the original mounting points,
and (b) are of a non-remote-reservoir design. The number
and type (e.g., tube, lever, etc.) of shock absorbers
shall be the same as stock. The interchange of gas and
hydraulic shock absorbers is permitted. External adjustments
of shock control shall be limited to two (2). No
shock absorber may be capable of adjustment while the
car is in motion.
2. MacPherson strut equipped cars may substitute struts,
and /or may use alternate inserts. Spring seat ride height
location may be altered from stock. Remote reservoir
struts and/or inserts are prohibited. External adjustments
of shock control shall be limited to two (2).
3. Springs of any origin may be used, provided they are of
the same number and type as originally fitted, i.e., coil,
leaf, torsion bar, and that they shall be installed in the original
location using the original system of attachment. The
joining of two or more coil springs by any means is prohibited.
The use of tender springs are permitted. Shackles
or spacers may be used to adjust leaf spring ride height.
Spacers, including threaded units with adjustable spring
seats, may be used with coil springs. Coil over threaded
body shock/struts are permitted.
4. Spacers or lowering blocks may be used between leaf
springs and the point(s) of attachment to the axle housing.
Hope this helps
end the confusion
The SCCA rule book is on linehere
http://scca.cdn.racersites.com/prod/assets/2014%20GCR%20June1.pdf