Never had a problem you just need to know how to install them right, do NOT WELD them is key. Had one set for over 6 years and the two people after me haven't had any issue's with leaks. Just installed my new set on my current car and no leaks again.
2001 Regal-GMPP handling, shift kit, tuned, ported Gen3, 3.6, N*, SLP dual catback, Aeroforce
70 Monte Carlo 12.5@109 waiting on new setup