i just installed the buschur drop in air filter, and my car feels noticebly slower. is it true that it takes the ecu a few days to adjust and etc and it should get better.. or should i just change back to stock right away.. really odd because i hear about several people gaining hp.

 

Did you reset your ECU? If not try that before going back stock. Disconnect your battery and wait like 5 minutes, than reinstall the terminal.