ALL AVAILABLE CAT-BACKS ARE BOLT-ON. All of which requires 2 cuts on the stock exhaust piping to remove it. If you want to pay lots of $$ labor to save your old exhaust, have the shop remove the rear cross member. Of course, there might be potential problems of something going wrong later on doing the 2nd method (as the shop would most likely know more about exhausts and piping and not suspension stuff).
[quote author=brugg90 link=topic=73923.msg1401677#msg1401677 date=1178841002]
has anyone heard of borla screwing up the bumper?....i just dont want to have to modify a brand new borla exhaust...by welding it.
[/quote]
You already asked this question last month.
http://www.mazda3forums.com/index.php?topic=74987.0 PM Midnight_speeder on what his bumper cutout now looks like. Good luck.