[E55 Bulldog]

I just installed down pipes and the questions I have are....

1. Can I run down pipes alone? I know I will get a check engine light from O2.

2. Can I run down pipes and BM3 tune alone or do I need gapped spark plugs?


So, like I said I have installed my downpipes today, The plugs I have are wrong ones so I need to order a new set. Im sure it will take about a week to get them so id like to put the car back together to drive and just break it down again once the plugs come in (really wanted to just do it all in one shot). I also have BM3 tune ready to run but have not tuned the car yet because I was hoping to get plugs in also.

So... are there any issue with running just pipes vs. pipes and tune vs ideally pipes tune and plugs?