I'd do an LS1 and something RWD myself. I like the L67 and all, but an LSx motor is pretty badass. I keep a look out for good clean S10s or even a Miata, for a little transplant.
LOLOL an LSx would kill a miata, all the handling they brag about would go down the tubes. And it's a womans "sport" car.:th_shakinghead1:
Its been done before... an LS1 Miata would clean up out there. Besides who gives a damn about autocrossing? Not me, I'd have more fun straight line myself....