I'm thinking that buying a higher mileage ls1 is probably the way to go if I am going to modify it anyway, and just start with a fresh rebuild and build it up how I like it. That way I get the car for cheap, and have money for the rebuild/mods.

I figured $8500 would get me a decent shape z28 m6 with 120k miles.
$300 for hone/line-hone
$500 for bearings/gaskets
$500 for forged pistons
$600 for h-beam rods
$1000 for a nice cam/valvetrain package
$225 for a double roller timing set
$500 for LT headers
$250 for tuning
$400 for a decent clutch
$200-$300 for an ls6 intake
$400 for a used n2o kit + 150 shot

So total would be ~$13000 for around a 'safe' 525-575rwhp. The rear wouldn't last on the track with hard launches, but for $13000, I dunno if you could build a faster street car.

 

Something like this might suit your needs:

http://cgi.ebay.com/ebaymotors/ws/eB...RK%3AMEWA%3AIT

Sounds like tranny needs rebuild, but with only 74k on it, engine should go for another 50k+ modded miles w/heads/cam & all the bolt ons.