I am planning on doing the full high flow cats and midpipe upgrade to go along with my Eisenmann muffler. Dunno when I am going to do it though given all my expenses this year along with getting married in August. Why not just take it to a good muffler shop? The secondary cats have nothing to do with O2 sensor.
2012 Audi R8 V10| 6MT| Suzuka Grey| Dallas Performance Stage 1.5 Twin Turbo| 817whp pump| 950whp on 109 octane| GMG springs| Klassen M52R| Toyo R888R| GT Tails| GT wing| Black Optic Grille| CF everywhere| Satin black badges
2015 BMW X5 35d|Mineral White| Mocha
2017 BMW M3 ZCP| Mineral Grey