Well you got the wrong forged parts. Our engines have oil squirters, so generally pistons are fine, rods are the thing to go first. No matter your injector size, your engine will be limited to roughly 200-250hp, which is when the stock rods will give out. Trust me though, 12psi on band aids and 12psi on a megasquirt are two very different things.
The MS kit isn't hard to do if you know how to solder, but search around, a few guys will build one for you, including Braineack, Wayne Curr, and Jeff CUlkinksonksinamey, to name a few. Others I'm sure will do it, but Braineack is most likely the most popular on this board, and the other two are west coast locals.
Looky, looky, a full section dedicated to MS:
ZOMG! A sticky of very important threads! You better ignore that.
SUPER Important Megasquirt Threads
How to make and install a MS: they should really rename this thread, it's title is a little confusing, huh?
How to make and install your own Diy MegaSquirt
Hopefully this will get you started.