Universal mufflers are created for use on a number of different vehicles so they'll need to be modified before they fit snugly onto your 2003 Mini Cooper's make and model. ... This means that universal fit mufflers could require professional installation.
Universal mufflers work fine on average cars but you have to find one that matches your inlet and outlet of your existing muffler. It also has to match in length and diameter. Then you have to cut off the old muffler and leave enough pipe in front of it so you can attach the new one.
A smaller muffler is going to give you a much louder sound than you would normally get with a larger muffler. The larger or longer the muffler, the less sound you will get. The smaller or shorter the muffler, the more sound you will get.Most popular mufflers do not restrict exhaust flow dramatically – and that includes chambered mufflers that are often wrongly accused of inhibiting exhaust flow and decreasing potential horsepower.
You can take your car to a muffler shop for a replacement, but installing a new muffler yourself is fairly easily and cost-efficient. To complete your muffler installation, you'll need a jack to lift up your car, a wrench, different sized ratchets, lubricant, and possibly a hacksaw.