95 Base conversion to G-Stock legal ClubSport?

[username]

n00b here. I just picked up a clean 95 318ti from a friend, with plans to mainly use it as a fun economical daily driver. But as a longtime autocrosser, I can't help but think about in terms of cone action.

I know it's a bit underpowered against the boosted Minis in GS, but it would certainly build character to campaign an underdog car... Or at least get the car into Stock-legal form in case the car ever gets reclassified in HS.

Right now the car isn't quite legal in stock - it's a Base model with the M-Technic plastic body parts and LSD added post-factory. I don't want to remove the diff, so the idea of a ClubSport conversion crosses my mind.

So I'm looking for help with some details on a correct ClubSport conversion, correct as far as the SCCA Solo2 rulebook is concerned. (I know it won't be a real ClubSport to those concerned about history, serial numbers, concours, etc...)

I did some searching here which answered a lot of questions, but a few details have proven elusive:

1) Springs - Were there different sport springs used between the 95 ClubSport and other years' Sport package? Any leads on part numbers or identification of pre-owned springs? I see realoem doesn't list springs, but instead suggests a visit to the dealer. (Might just do that but was wondering if anybody else already has...)

2) Rear hatch spoiler - These were never available from the factory on the 95 ClubSport, right? Anybody know if these were just attached with sticky tape, or maybe holes were drilled for its installation?

3) Interior differences - Were the seats the only change to the ClubSport interior over the base model? Are the only seat differences being fabric type (neat cloth in center and leather bolsters), or were the seats shaped differently or equipped with different adjustments? I'm under the impression color doesn't matter (under the comfort/convenience allowance) but if anything is functionally/materially different then it needs to be addressed.

Thanks in advance...

Aaron