Got to agree with what's been said - had a 300TDi RRC, then 'upgraded' to a TD5 Disco. 12 months ago I got rid of that and got a TD5 90. It's noisey, doesn't have heated seats, air con, electric windows, etc, etc, etc, but it's been great. A few niggles, but nothing major - even the fuel economy surprisingly good (although doesn't go a fast as the Disco, but it is as aerodynamic as a breezeblock.
Go for it!