Ok car has had k&n stylie air filter removed and exhaust replaced ( old one had bodge repair on the flexi joint and back box had been replaced with a tiger s/s jobby with 6" pipe ) with standard exhaust , plugs oil etc have been replaced and garage are cleaning the injectors with some sorta ultrasonic jobby . So with all these changes should i reset the ecu or will it sort itself out . Car is a '98 HLX 1.8 .

your ecu should reset itself as it changes to adapt to driving styles it does the same with componects on the car as long as you still have all ur sensors on the car lamba etc