And you will remain at 225 horsepower.
Your horsepower rating is without the exhaust, intake, or any restrictions.
So, no matter what intake and exhaust you put on there, it's still a restriction. So, you will not increase anything beyond your 225 number. Unless you remove the exhaust, headers, intake, accessories, and transmission, you will not increase beyond 225.
Right now, at the wheels, and after all the restrictions, you actually have around 190 horsepower.
Go for whatever sound you want, but know that you're still at 225 engine hp.