So I found the exact muffler I want it's the Magnaflow 14815. However it is 20.5" length from body to muffler tip. The stock muffler in a Diamante is about 29" and if I wanted the tips to show, which I do, it would need to be 32". How can I extend it?

weld some pipe onto it?

That is the logical answer, right? lol. Our cars are so anti-modifying that we even have huuggee mufflers that cannot be easily replaced by aftermarket parts.

there should be a join in the exhaust right around the rear cross member. you'll have to cut the rear section and insert some pipe.

and yeah, there aren't many aftermarket parts available. I mean, who would want to modify a FWD 4 door sedan, right? :nuts:

good luck!