Just ordered an AR 3" catted downpipe for my mini and I'm planning on going to stage 2 ( I have all the required parts just need to send in my ecu) I know that the downpipe is going to give me a cel my question is will my car still drive fine with the cell until I decide to get tuned?

 

Is all about the CPU...ask the shop how's going to do the work to leave the programming like it is...if you are running fine right now...you will after..(NOTE: I just got installed in my R56 a 45mm turbo with no MODS done to the car and is running fine, like there's still the same 37mm but tunned down)

 

Yes will drive fine your 02 sensors will burn out top and bottom when they will who knows. The cell is because your taking the cat out 02 sensor is for emissions.
Depending on what Tune you may ask and get the engine light to be tricked and turned off. By my experience if the engine light blinks off and on you engine will cough and sputter then worry. Just my opinion everyone has different set ups..Enjoy the new found HP and sound..

 

The car will run fine, the cat is only there for emissions and the secondary O2 sensor is there to monitor cat efficiency, you'll only make the EPA mad.