Tuning / maintenance on T4 2.5TDi ACV engine

Good morning forum users,

We are in the process of deciding whether to buy a '98 VW T4 Transporter with 2.5TDi (102BHP ACV) and 200,000miles on the clock!

I currently own A4 1.9TDi AFN for three years and I've learned so much about mechanics by doing some DIYs. Being a different engine size, I would like to ask few questions about ACV engine and immediate maintenance upon purchase (if we do decide to go ahead):

• Cam belt is due, what else to service whilst the belts (I believe there are two) are being replaced? - The tensioners, water pump, cam shaft seal, thermostat, oil, coolant, filters (air, cabin, oil, fuel)... are there any other components to replace for a good measure?

• The factory braided black vacuum rubber hoses are frayed: 3-4mm ID silicone a better replacement for this? I've done this on my A4.

• I'm not sure if the turbo has been cleaned ever: Is it a DIYable job for turbo removal and physical cleaning? Again, I did this on my AFN turbo so I'm familiar with cleaning the turbo, but not familiar with 2.5TDi set up and how to get to it.

• Diesel additive on this engine? I've been using home made mix of 2 stroke oil (low ash) + 2-EHN (cetane enhancer) on my AFN for less engine noise and bit of a kick. Do other 2.5TDi owners do this?

• Remap: Will it be a physical chip swap in the ECU or via VCDS?

Hopefully I can get some idea before we decide to go for it, and I very much appreciate any thoughts or advice on ACV engine.

Many thanks as always and happy motoring!