I had a group buy on for these a while ago, and finding new ones are a real problem. On top of this you will be looking at more than ?400 a set, if indeed you can find them.
This topic is discussed in detail on http://tdiclub.com
all the time.
The americans all use injectors as a starting point as they have only recently starting getting PD engined VW's.
The alternative to injectors are injector nozzles with the 0.216 opening as per the transporter injectors. However, while the yanks claim better power, the tuning guys dismiss them.
I have a 150PD TDi Turbocharger I was going to add to my Passat, but it is looking like major job to fit it to my car due to the engine sitting longways instead of transversly like the Golf. It is in the for sale section here Clicky
Simon at http://www.centralvwaudi.com
is in to tuning the non-pd TDi VW engines and is worth talking to as well. I am still planning to take my Passat to him soon to see if the turbo can be fitted along with injectors. However if I sell the car and the turbo, I will be looking for either a Cossie or a 150PD Golf so that I have a better starting point for tuning. Dont get me wrong, no detriment to the 110TDi, but if you have a Golf 110/90 TDi you have a much better starting point than me in my Passat.
My 2p's worth anyway.