As with just about any motor out there; if you dramatically increase the air and fuel without upgrading to forged internals, you take the chance of the rods and/or pistons falling short of holding up under the increased load. You can safely up the boost to 9psi (or controversially; 10psi), and with a few other upgrades i.e. intake, charge piping, etc, you can easily get the car running safely at 200hp give or take. Anything more than that and you need to start thinking about pistons and rods, fuel injectors and delivery, exhaust, list goes on and on.
Another thing to keep in mind is that they only made 4500 of these released in the US (250 in Canada). Theres a lot of parts that are specific the the speeds, and some are not easy to find and/or afford. If you want parts for these cars, oem or otherwise, you,re going to pay for them one way or the other. That being said, to some like myself and most of the other people in the MSP subforum, these cars (when operating nominally) are ******* badass and worth every amount of effort and money necessary to own/maintain one. But if you're afraid of commitment, you'd be better off with the cheeseburger.