So I want to get the car tuned and eventually will be installing a turbo kit. Do I need a downstream o2 sensor? Currently have code p0141 for downstream heater circuit, it bogs out at 3000rpm cause its not there. I unplug the upstream and it runs fine. Thinking about running a p28 and converting p2t with jumper harness. Will that solve my problem with the right basemap? Just not sure the best route to take. Should I cut out and weld in a bung for downstream regardless even with no cat. Tell me what you think, thanks in advance.