IdahoLT1

Last year my firebird would vibrate a little right before the end of the track ~95-100mph. I recently replaced the clutch and flywheel and now it is way worse. Im not sure if the flywheel needs balanced, driveshaft changed, rear end work, engine work or anything else? I got new rims and tires, balancing and alignment but it didnt solve it. Someone point me in the right direction.