What are you trying to accomplish? I think maybe you should work on bolt-ons first to get an idea of what direction you are heading in with your car. Working on the engine isn't as easy as depositing some forged pistons in through the intake manifold (MAN IF ONLY IT WAS THAT EASY!). You'll need to know what you're doing before you destroy your car in the process.

I don't know what kind of engine (or even car?) you're talking about, but here's a good read about bolt-ons on GM engines anyways...

10 Best Budget LS1 Bolt-Ons - GM High-Tech Performance Magazine

 

I don't mean to offend you but that was a terrible article. Royal Purple is not going to give you 5 HP. And notice only SLP products were featured for gains in HP. GMAB.

If you want to figure out the best route to do something, look for mass consensus on a forum then do your own research.

 

The stock auto trans is rated for 325 lb ft of torque. If he doesn't plan on going past that he should be fine.

 

A 4cylinder ecotec is not an LS1 engine, none of those bolt ons apply to his application

 

Just because that's what it's rated before doesn't mean that it can't blow at lower power. Lots have had problems with it going in the mid 200's when driven hard.

 

And just because some have problems doesn't mean his will lol. His could hold more than its rated for. And there have been problems with built ones. All a part of modding a car.

 

Please pay someone to build your engine if you decide that's what you want.

 

I would say the best thing to do is get on the phone with zzp, tell them what year/model Cobalt you have, tell them what power/torque you would like to reach, and let them advice you. Can't go wrong

 

what would be the best tune to get ? I've heard of some but figure maybe you guys can give opinions

 

Get someone to hp tune you.

 

Collect money, drive up to ZZP for a long weekend, hand ZZP your money and key say I want this much power. Let ZZP work their magic get car back with said power and drivability