Fair play mate when mine had gone I was pissed and I still had to fork out part costs even on warantee.
They said you're lucky we are doing it twice for you! I said You should have done it right the first time
It was a rapid Passat 2.5 did 140MPH no problem, but being diesel the viens just kept closing up. Got rid of it in the end, but I know what its like without the car for months.
I've got a 160PD with Garret goes well and defo better than the Ko4's IMO.