Don't think there's any grounds for worry. My 90 was converted to 300tdi / R380 in 1998. Gearbox sits on LT77 mounts and the engine sits about 50mm further back than a standard 300tdi. Coolant hoses etc are all standard and fit with no problems. I only had problems with the fuel filter. I retained the bulkhead mounted filter. A 300-tdi type fuel filter fouled the air filter hose hence I retained the old-type fuel filter for 15 years. Lately I decided to change it and found that a citroen xsara fuel filter fits the 300 tdi Boch filter head and is 30mm shorter than standard.