Stu,yes m8! it depends on how hard he's driven it if not about 1/2 @ least!as said above this is his 3rd set in a short amount of miles!Ive told him not to drive(hard till he sorts it) as next time it could be alot worse than spark plugs!CAR HAS GOT ABOUT 150 COMPRESSION ON ALL 4 CYLINDERS|(No3 HAS 145) if that helps @ all! boost is set @ 22psi!

FOR ALL HELP