Ok so I got my exhaust from Mina for my 07 STR. Looks BEAUTIFUL! Installing it and the 57.2mm clamps that are included seem to be too small. Tightened all the way down I can slide the muffler right off the stock pipe. So I took the center piece out of the clamp to get a little more room to tighten it. All the way as tight as the clamp goes using a half inch impact, the muffler still slides right off. Anyone else have this issue? I think I need smaller clamps.

 

I had the same problem when I installed them on my 2005 STR.

Here is what I did:

After playing around with a number of things I found a piece of exhaust pipe that was the perfect spacer. It slid over the existing pipe fine but was too large to fit inside the Mina exhaust. It took some time but I carefully ground that piece of pipe down until it was a slip fit into the Mina exhaust.

Pretty tedious and it took a bunch of test fitting but I did NOT want to modify either the stock pipes, just in case I wanted to back to the stock mufflers or the nice new Mina exhaust. This spacer was the only way I could think of to fix the problem without touching either the stock pipe or the Mina pipe.

Must have worked because I have had the Mina boxes installed for over 50K miles!
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Good to hear! I actually found and cut some pipe to use as shims to take up some room between the two pipes. Like you I really don't wanna have the stock pipe messed with. I thought of maybe using an exhaust flare tool to bump it up a little so the Mina exhaust fit more snug.... After work I'll be pulling the car back in the shop and playing around some more with it. Something that should be so easy is turning into a project!

 

I was surprised a bit because I would have thought the MINA was made for both the regular and the SC 4.2L. So I was expecting the MINA pipes to be a bit smaller since they could work on the 4.2L NA.
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Yeah that's what I thought to. Anyway the shims (piece of exhaust pipe) I cut and fit in between the Mina pipe and clamp seemed to work! Honestly I just think smaller clamps would of worked. My exhaust clamps (57.2mm) that came with the exhaust kit all the way tightened were still too big. Perhaps they should start using 52mm or 53mm clamps....
Either way it's done and on! Just a lot more work then I thought it would of been. And lucky for me I'm a mechanic and have access to a garage, tools, and a lift! Otherwise, what a nightmare this would of been for those less fortunate without these things!
Oh, I also cut 2 more notches in each of the Mina exhaust pipes to better clamp down. I will post pics

 

Modified pipe, not sure why this is upside down

 

Well I was going to put up before during and after pics but for some reason they are all showing upside down.....