The muffler on your 2003 Acura RSX will not need to be removed, but it will need to be lowered when installing the (discontinued) Curt Trailer Hitch Receiver C11154 as you can see in the attached installation instructions.
If you check out the attached video of the Draw-Tite # 75650 on a 2009 Subaru Forester you can see one of our installers walking through the process of lowering the exhaust.
Please note that per the Curt warranty you will need to use a support strap, like part # 18050,... view full answer...