ITs just annoying and doesn't affect anything but my gas mileage (yet) but anytime I try to accelerate and the car is below 2000rpm (starting from a red light, shifting into 2nd and to less effect 3rd) the car shudders and misfires. Not clutch chatter either, with the exhaust leak (Fred: The gasket blew out, now its loud! Funny though) I can definitely tell its misfiring. Not throwing any check engine lights though.
Coil?
Spark plugs/wires?
Its a DOHC so they're even more of a PITA to change than normal.