OK
TS is correct of course . .
For what its worth.
There was a running production change on the rods. Look for the thread on sintered rods for the 2.0. There is a concern that the later rods are less robust than the earlier rods.
There are a lot of cars running around with 300 - 325 WHP that are apparently as reliable as the stock 2.0 cars.
There are a number of cars in the 390 - 400 WHP range out there. Several of those have had issues with the syncros which is believed to be a result of the high horespower. Dave has stated that he believes that 400 WHP is the limit for a reliable 5 speed transmission.
The GMPP tune provides less peak torque for the automatic cars than for the 5 speed cars. There are a number of assumptions as to why this is the case, but there is also confusion. Some say that the auto is better able to deal with higher HP values than the 5 speed, but wonder why the factory limited torque. My personal opinion, and its only an opinion, is that it has more to do with shift quality and firmware in the transmission than its ability to handle the added power.
There is a body of people who believe that the axels are ok up to 400 WHP but that figures above that can lead to failures.
Resist at all cost mucking with the rod controlling boost. There are a number of posts looking at this as a road to power but most have either gone back to stock or given up on this path.
The best power mod is the GMPP tune or tune of your choice. Considerable "free" power to be had.
The only mod other than a tune that is proven to add actual HP is a high flow cat. By all means, get one.