I tried an Mazda AZ-1 "project car" about a year ago, and here's what I found.
*** Bought used AZ-1 at Mazda Used Lot ***
3rd: Mazda AZ-1 Race (racing flywheel)
2nd: Mazda AZ-1 Race (racing intercooler)
1st: Mazda AZ-1 Race
1st: Mazda AZ-1 Race (Stage 1 Weight Reduction)
5th: Clubman/Tahiti
4th: Clubman/Tahiti
1st: Kei/Tahiti (Stage 1 turbo)
1st: Kei/Tahiti (Racing Transmission)
1st: Kei/Rome Short
1st: Kei/Rome Short
1st: Kei/Seattle Short (Stage 2 turbo)
1st: Kei/Seattle Short
2nd: MR/Grand Valley East
1st: MR/Grand Valley East (Super Soft tires)
1st: 80's/Trial Mountain (Stage 2 WR)
1st: 80's/Deep Forest (Port Polish)
1st: Pure Sports/Laugna Seca (Engine Balance)
1st: 80's/Tahiti (won ~394hp event; and 125,000 prize car!)
6th: GT Cup/Red Rock Valley (~394hp, getting tossed on the straights, not bad in corners)
6th: GT Cup/Grand Valley (~493hp, lost on the straights, not much time made up on corners)
*** No more unique events to win ***
There aren't that many fun Kei cars, but this is one of them.