I personally don't like the hollow sound tips like that make, kind of a resonated muffled noise. Are you talking about tailpipes that expand out to 3.5" or just tips you can buy in any "performance" isle in the local auto parts store....doesn't really matter, my $.02 is that it won't sound good either way. The add on tips make it sound raspy like a rice rocket but with a lower tone. and the bigger tailpipes, as stated make more of a hollow resonant sound. I should actually be the last one talking about this since I intentionally put GT pipes on my LX just because i didn't want the hollow noise or chrome look (i could of gotten the chrome LX pipes for like $40 more for both), but do whatever makes you happy since it is, after all, your car.
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'84 Mustang 5.0 LX
My car