imprezzedEJ25

My 98' 2.5 RS makes a vibrating noise when the throttle increses. It occurs at 2500 rpm and it sounds like the heat shield against the exhaust but im not sure. Has anyone had the same problem and if so what was your solution to fix it. The sound doesnt the way the car revs up it just is embarrasing. Please help.

Also I am new to i-club.com and was wondering what web sites were the best for mods for the EJ25 . Thanks again.