Just bought this car, and I know nothing about it. I'm trying to replace the turbo and have no clue which one to buy. I plan on having a mechanic friend install it, but i need to know whether my 1998 diesel jetta has a ko3 or ko4 flange....does that make sense? I plan on trying to buying used. Which turbos from which cars would fit in mine? I'd appreciate ALL the help I can possibly get. Thanks vortex!