ScorpioV8

First, I'm over in the UK so Chevy parts are not quite as easy to grab...

I've bought a 2005 L33 out of a 2005 Silverado 1500 with 20 K on it. Minor damage to one cylinder head which might weld up. (799 heads)
I've been browsing this forum and reading what seems to be the way to go, so I'd value comments on the plan. I know only some of it is INTERNAL mods but they all go together, sort of...

I want to up the power a bit when needed but I don't want to loose economy as it will be a daily driver. (Except when using power).

LS6 cam and springs/pushrods or Comp Cams Thumper?
LS6 Intake and Mechanical TB. (can I still use the truck fuel rails)
Long tube headers of some sort - it's going in a F**D Scorpio (UK) so I will have to do some careful research there, 1200 Kg car, 3.63:1 final drive, LSD, 700R4.
No CATS needed

There is an interesting article here http://www.carcraft.com/techarticles...der_heads.html but I'd guess it might be beyond a remap of a stock ecu to deal with? MS can deal with whatever though, once I get it running and on a dyno.

OR remap the one it came with, keep the 4L60E and drive by wire throttle.

Lots of choice, or I could just run it stock for a while, cold air intake and headers, what would it make like that?

Thanks...

Gareth