the main advantage of the GT TDI is the running costs
the main disadvantage is the cost of the car - but the savings on fuel offset this
based on the paper mpgs i've created this savings table this shows how much you would save in a GT TDI 150 against a GTI 1.8T 150
Mileage | Saving £ |
10000 | 388.9827363 |
11000 | 427.8810099 |
12000 | 466.7792835 |
13000 | 505.6775571 |
14000 | 544.5758308 |
15000 | 583.4741044 |
16000 | 622.372378 |
17000 | 661.2706516 |
18000 | 700.1689253 |
19000 | 739.0671989 |
20000 | 777.9654725 |
this is based on the petrol being 101.9 a L and diesel being 106.9 a L
engine wise the TDI's have a better reputation than the petrol except they aren't as tunable expect 260 bhp tops from a 150 where as the 1.8T can go to 400 bhp, however in real life you want torque and as standard the TDI 150 has more than a boxster a clio V6 and will go from 40-60 faster than a type R
service intervals are the same at every 10K except the oil in the PD engine is more expensive that the petrol stuff.
if i was looking at buying a MK4 then unless you want to tune it go for the TDI 150 same spec as the GTI 1.8T 150 and almost identical performance. except you can go for pretty much double the distance on a tank.