Hey guys, it turns out to be O2 sensors. The indy says I need both front and back. I've already used the search function and went 4 pages deep but am still slightly confused as to where to purchase it. Should I purchase from bavarian? or somewhere else? It would also be terrific if you can provide the part number for both.... thanks guys!

I went to bavarian and came up with two part numbers. Can someone confirm and/or clarify? Also maybe shed your opinion on the part?

Thanks!

Part # : 13 802
Part # : 15 109