Engine Choice Help

[jam199wins]

I am really indecisive and cant choose what motor combo I would like to do in my 03 4.6l. The options with cost estimates are
$1000 Supercharger w/ 100k mile motor w/ tune
$1700 Supercharged w/100k mile motor w/ forged piston rebuild kit w/ tune
$2000 Supercharged w/ old motor that needs head work and rebore w/ forged w/ tune
$500 NA w/ 100k mile motor

The 100k motor we are not sure how long it will last as we just got it $500 with the computer, but it seems it ran well.
The motor that needs head work has a solid bottom end and after work would be fully solid.
I also have the Saleen supercharger and full setup, just would need to have the car tuned for it.
I hopefully should be running this car as a daily-ish at around 5-7 psi if supercharged.
Any opinions would be appreciated.

 

[OneSick99GT]

I'm full NA build and should have went SC. The amount of hp you gain from a supercharger is well spent. I'd go option 2($1700). At least when rebuilding the block you can get an idea how badly abused the motor was. Without tearing it down you will never know. And why would you want to throw a supercharger on there if you have something more serious wrong with the motor. I would upgrade the crankshaft along with it. That way you know down the road if you want to add more pony's your not concerned with old crankshaft going. The 4.6 blocks are good up to 400 rwh with stock crankshaft. Anything above that and your pushing the stock crankshaft. Do the rebuild kit, upgrade the crankshaft and slap that SC on it. Best bang for the buck and hp to $'s.