Tough call... you said you don't want to do major modding, just wheels, drop, some tunes.

If you'd said performance I'd say C6 all the way, but the Bimmer will be a tad more livable as it's higher and has rear seats.

That said, I daily drove my Z06 for over a year when I first purchased it... they make great DDs if you leave the mods to a minimum.

The new '08 vette has teh 430hp LS3 which has tons of power bone stock and a great interior even w/ the base model.

I say get an '08 vette, get the cheap painted wheels, throw on some wheels, lower it 1" w/ the factory adjusters, get some mufflers and call it a day. The stock stereo is quite good and w/ the DVD/Nav/XM system there's not much in need of changing.

HTH,
Brian

PS w/ the vette you can get the clear targa panel... which makes closed roof driving very very fun.