My car has a cai/ram air that I made w some APC plastic parts (2.5"). The first time I installed it the engine had trouble to accelerate. I made a reducer pipe on the Maf adapter w a piece of pvc and foam sandwiched inside it. And since my Maf was already on the verge of death, I replaced it w a Celica unit, the best $80 bucks I've spent on this car. It made a big difference, specially w the ram air tubbing connected. No low end hesitation and a great sound at wot. I've had this combination for two years. No problems. It pulls better at med/high rpm, since these engines, to be honest, have their powerband.