hey mate,
recently on mine i started little cheap mods. the first thing i did was to help the breathing. changed the air filter and got a straight though exhaust. i kept to a paper filter and nothing k&n fancy. in my opinion those can let fine particles in. my exhaust system has a can in the middle which is hi flow and nothing on the rear. helps with exit angles as the pipe is tucked away nicely and doesnt catch anything. the middle can is protected as well from structural beams etc. I think its a good design. the exhaust guy that did it for me has plenty of experience with landrovers. its basically the same thing as a mid muffler removal except the other way round. in mine it dramatically increased the driveability. runs a lot smoother.
i also just recently tuned the low end fuel adjustment on the pump. i havnt done the full tweak as i dont have an EGT yet. that helped a bit too.
last weekend i readjusted the valve clearances. that helps too if yours are a bit out and i also pulled out the injectors and cleaned them and put new copper washers (as some were leaking). if yours has done 400k maybe the injectors could use replacing or testing at least. most diesel places test for free.
for those mods i did, the power increase is marginal but it sure runs a whole lot smoother and is nicer to drive. i think once i get an egt i might invest in a better intercooler and then tweak the boost on the injector pump. i think those should create more noticeable power.
all very worthwhile though. just read the fuel tweaking instructions very well and remember that it could be detrimental to your engine if overdone.
