hey when i accelerate i got smoke coming out from the muffler and smells. i have a check enigne light for the catalyic and for the coolant. could that be related? ive already changed the oil to be on the safe side.

 

If its blue smoke then your burning too much oil, which tends to happen when your cat is fried...not sure about the coolant, perhaps its low, or you have a leak somewhere...If your throwing a CEL for the cat, that means its probably fried and needs replacing, in which case, go with a high-flow unit, they dont cost anymore over the OEM one, plus you'll get some "slight" gains!