New Engine

HI
I'm looking at purchasing a 1985 G, problem is the engine is siezed. I haven't gone to look at it yet but from the pictures and a conversation with the seller everything else seems ok, but we'll see...
Any way I'm hopeing for some advice on a replacement engine. I'm not exclusively thinking that it has to be a Mercedes engine if someone has an alternate suggestion.
Basically what I'm looking for is a turbo diesel engine with reasonable power (100+ bhp), that won't cost the earth to buy, install or run. Not asking much is it ??
One more little issue, I live in the South East of Ireland and to be honest I can't remember the last time I saw a G Wagen so I guess there's not many/any of you owners down here so if anyone has some advice on where I could get a replacement and what (approx) it might cost to buy and install assuming it is only the engine needs changing it would be wuch appreciated.

Martin