the g35 sedan makes a good family car too.
stillen makes a sc for the VQ35 too.
HKS and Vortec makes a SC apps; JWT, Greddy makes twin turbo apps.
by all means, G35's were compared against the Bimmer 3 class and beat them all. well...except the M3. The M3 is a different ballgame. You wont find an Altima being compared to the 3 class, you only see them being compared to the Maxima
and other Japanese import cars ie. Camry, Mazda6 (Mazdaspeed6?), Accord.
If you want sleeper, the Mitsubishi Evolution RS takes my vote. All the goodies of the Evo VIII and MR, but in a lighter package. And it looks like a standard Lancer...the downside, No standard A/C - It's an option
And it wll give a Porshe Carrera 4S a run for it's money, 13sec 1/4 times, 0-60 in less than 5.5sec, and 0.95g lateral handling and have confidence in the rain with the AWD all the while still seating 5 nicely for about $28k.
But it's your money.
I'm just saying look into other options.
You never know that the grass could be greener on the other side.