Hi Yeti,
I have recently purchased an Assetto Corsa from Dicky Grace and would highly recommed both the car and Ricard Grace Cars.
Although I suspect many of the comments made on here regarding "real world" differences in driving are correct, having now driven both, the A/C does handle a little better in my opinion (lower, with stiffer springs and quicker steering) but for me, the main reasons for getting one were:
1. the look of the car, slightly lower, with the different wheels and interior that contrasts so well with the silver bodywork; and
2. that "limited addition factor", that makes an already special car (I think all 3200's are special and its a real "event" when I see one) even more so!
Ultimately, it will depend how quickly you want to make your purchase, but I would say as with many things in life, the extra time and effort needed to get an A/C will be rewarded with attaining something special.
Good luck with your search.
MM