sounds knackered. probably all the times you have sat in the driveway and revved it. (nah, maybe im being a bit harsh here)
well, it aint an exhaust problem, you could run a pure straight through and it wouldnt knacker the engine (just harm the power a bit)
if its using oil, then from what i know it aint the HG. its piston rings, from the sound of it. if i were you, i would buy a haynes (bet you got one) and take the cylinder head off yourself. then see if its rings or what.
it even could be you not putting the dipstick back in properly, and overfilling it :chin:

well, it aint an exhaust problem, you could run a pure straight through and it wouldnt knacker the engine (just harm the power a bit)
if its using oil, then from what i know it aint the HG. its piston rings, from the sound of it. if i were you, i would buy a haynes (bet you got one) and take the cylinder head off yourself. then see if its rings or what.
it even could be you not putting the dipstick back in properly, and overfilling it :chin: