Would this be safe....
That being said the one thing that bothers me the most is you saying that you have never had the car on a reliable dyno, makes me wonder if you have a reliable tuner, which is the biggest factor in keeping the stock bottom end alive under boost.
An sts or "cheap" custom job will get you there. But you have to ask yourself if you want to buy the setup one time and have all the parts and just up the boost when you forge the bottom or if you want a 450hp kit and do something different like a front mount post forged parts? I am in the same boat and probably moving mine to the front right now.


