I'm seriously thinking about buying a cheap E39 530d which needs a new engine, plus a replacement engine to go in it.
My question is whether while the new engine is out, are there any internal mods which can be carried out to it to improve its performance? Obviously a big part of carrying out internal work is the removal and refitting of the engine, but as it will be out already, I was wondering if I could save a few quid?
Once it's in, I shall be going down the chip tuning route as well, and was wondering which one is best in your enlightened opinions?
Many thanks for your help.