Guys i might have to return my car to standard, its running a 3" bore turbo back decat exhaust and is mapped by ECUtek.

Will i have to remove this and have the car mapped back to standard or can i sell the exhaust and ecu as a package plus a swap for the buyers ecu?

is this safe to do or a big no no?

Thanks.

P.s if its a no no how much to have it mapped back to standard roughly?