Ok, so recently I did my muffler delete it sounds great, loud, mean. I had this on before and everything was fine. Winter is now gone and I went to the shop to cut the muffler's off and weld the straight pipe's again. I have this weird noise coming from under the car on the front passenger side. Whenever I accelerate between 2k - 3k Rpm normally not at WOT it has this metal vibrating sound... It's like coming from the Heat Shield or something. I lifted up the car everything is tight nothing loose! Everything looks perfect! What can it possibly be?! I' very frustrated with this. I looked everywhere around on our forum haven't found anything.

 

midpipe brace rattling against the midpipe. You don't have the hangers anymore from the muffler, so it's likely your midpipe is marignally lower and is now contacting the brace.

 

I have the support, they installed it one by the exhaust tips where the muffler was holding on & the other he attached it to the alluminum shield piece where the muffler is covered.

 

Right, I should clarify, the supports you do have are not *exactly* in the OEM place, probably. The midpipe is already pretty close to the midpipe brace even with a completely stock exhaust. It's possible that your welder put it a smidge too high and it's causing your (right tailpipe) to hang a touch lower than it would otherwise.