It wasn't too bad apart from the fact the differential doesn't feel right at all when you tweak them. It feels like it spins the inside wheel far too much no matter what diff' setting you have. 20 on Vicious seemed to work fairly well.
Even with the original engine and just changing it to RWD it was still good fun to throw it into a corner and have the rear end swing out for the right reasons.
I know you are/was a bit of an FXO whore and love it's FWDness, but you should try it with RWD if you can get hold of that mekanik/tweak.