I have an 88vert n/a. I replaced the original mufflers with a pair of racing beat mufflers. The car came with what appear to be aftermarket flow thu cats - 2 small cans on a pipe that connects from the header to the Y pipe. The setup sounds ok, but under load the noise level drowns out speech, radio etc. I am thinking the cats need to be replaced to improve the situation. Any suggestions?

 

If they are actually high-flow cats, there's not much you can do besides sticking restrictive stock replacement cats back in. NA rotaries can be very loud, so getting the noise level down without reducing power isn't so easy. Pre-silencers/resonators are another route, but the noise reduction of a high-flow cat should be the same or better.