I've got a 90BHP 1.9 TDi MK3 and I'm pretty impressed with it. If it had 130BHP I'd regard it as something worth keeping.
I've had a good look round at the various VAG models with the 1.9 TDi and see that the Mk4 Golfs got 100,110,130 and 150BHP versions. Along those lines anyway.
What is the difference? Is it turbo boost level? Injector size? Intercooler? Internals?
I did a google search and it looks like a chip swap can turn 90BHP into 115BHP. Are these numbers realistic or marketing bull sh!t?
Are the higher powered versions based on the same block and head?
I had a quick read of this:
http://www.dieselbob.co.uk/tuningmethods_plus.shtmlSeems to suggest that injectors, mapping for more fuel and intercooler improvements are the way to go.