[kwanza]

A good flash tuner should be able to resolve the issues. I had the factory reflash done by dealer and still have had 0300 issues, besides the factory tune is too rich. Since my custom tune i have had no issues with driveability.

Also you may want to have a mechanic inspect the car, to sort out any issues.

Choose an evo specific tuner, this will probably net the best results. I can vouch for RRE in Santa Fe Springs, but they are probably too far from you.

I would keep the aftermarket parts if they are of good quality.

Or you can try to learn to do it yourself like others have suggested.