Hello,
Excuse me for this real newbie question...
I have a 1998 convertible camaro with 3.8 V6, a magnaflow exhaust was installed like 2 years ago, now I want to check the air filter by a K&N one
(33-2118).
My question is : will I have to reprogram any ECU? will it automatically adjust?

 

There is nothing to adjust for. Your just removing some small restriction. Reprogramming is only needed when you change the dynamic of how the cylinder is charged. (CAM, rockers, porting, bigger injectors etc...)

Now reprogramming may add a little pep as the program is less focused on emission and more focused on preformance. Reprogramming combined with your upgrades would feel a little better then either upgrades would feel separately.

FYI: SLP did a upgrade like this to their 3800 RS version and did not reprogram the PCM.

 

I would wait for more significant mods before an A/F tune.

Next you should be considering an SLP CAI, Whisper Motorsports Lid and Headers/Y-Pipe with high flow cat and bigger S-Pipe to complete your exhaust upgrades.