Anything is fixable, but Sean is right, without the diagnostic software it'd be a slow and very expensive process. Have a look on Paddocks website for a comparison of costs involved with fixing a broken TD5 compared with a Tdi. Scarey stuff I reckon
Example... exhausts for a 90.
200 Tdi
front pipe: £17.30
middle pipe: £38.69
back box: £32.00
300 Tdi Non CAT
front pipe: £21.25
middle pipe: £32.00
back box: £40.00
300 Tdi CAT
front pipe: £224.50
middle pipe: £32.00
back box: £40.00
TD5 (Early)
front pipe: £125
middle pipe: £105
back box: £75
TD5 (Late)
front pipe: £125
middle pipe: £95
back box: £75
If you're going to go for a Tdi, the difference between a 200 and a 300 is largely negligible (as long as you ditch the cat, if it has one, and block up the EGR on the 300), buy a sound chassis and bulkhead combination first and choose the engine last
Cheers,