[darrin]

tun, what are you using for headers? Reason I ask is your '87 came stock with headers that brought all exhaust gasses to a single outlet feeding into a catalytic converter (a "1 out header") which would mate with a muffler that has a single inlet (a "1 in muffler"), yet you're looking to buy a muffler designed to attach with the header type porsche used on 911s prior to adding catalytic converters -- a header setup that separately moved the exhaust gasses from the left and right cylinder banks to their own individual outlets (a "2 out header"). Since you also inquired about the M&K premuffler, which is only compatible with a 1 out header, want to make sure you're looking for the proper muffler for your car.

Assuming your '87 still has its stock headers, you'd need to get a 1 in muffler, which M&K, etc. also make with a 2 out tailpipe configuration. Also, keep in mind that since the trim piece under your bumper only has a cutout for a single muffler outlet, you'd also need to change/modify the trim to accommodate the dual outlet muffler configuration you ultimately select.

Finally, it's my understanding that, due to the more balanced nature of its design, a muffler attached to a 2 out header is going to sound different than that attached to a 1 out header -- i.e. the sound clips others have provided of their 2 in, 2 out mufflers may well be significantly different than their 1 in, 2 out variants. FWIW