Is a tune necassary with a downpipe? If i install one would it be bad for the car as a dd to drive with it without a tune?

Same question goes with an intake and a CBE

Pretty much just want to know if having those things on your car not necessarily at once without a tune would be harmful.

Thanks.

 

you will run richer, not harmful... i have a full tbe, intake, exhaust mani and o2 dump and no tune yet.. i just dont rip it everywhere.. getting tuned soon tho