its not nice when the car doesnt go where you want it to go! some sort of undertray may sort it if you dont seem to be missing anything ?
 
get them on the bay. would that solve the odd misfire when its raining aswell?
 
good possibility it would, did any mk2's come with undertray's as standard? would be worth a go if their next to nothing otherwise i wouldnt bother if its only the "odd" one here and there