yesterday i noticed the car kinda surging while cruising at around 40-60 mph...not hugely noticeable, like the tach wasnt even moving but i could feel it and hear it in my exhaust...also, dont know if its related, but sometimes under deacceleration from a moderate romp, the exhaust will let out a loud pop..not backfire or regular exhaust popping but just a "poof" sound..
if they're not related, i'm not hugely concerned about the exhaust..but i am worried about the wierd surge..anything but opti will be fine with me

btw, it still has full power and doesnt do this during WOT...at least not that i can tell
FYI - opti replaced last nov. plugs/wires replaced a month ago, coil replaced last nov.