2000 X5 4.4i Engine refurbish

[Sack]

Hey guys how are you?

Im here for service till 2013 and bought an X5 year 2000. now i have enough time to do a complete overhauling with Faceliftupgrade. Therefor i also want to refurbish the engine, integrate the Air suspension 2 instead of the first series what is already in there, repaint it and and and... know you think for sure why is that nut doing that? so.... the first is i want to learn more about my car because i want to repair it by myself. and when i go back to germany... trust me its expensive going to the Bmw service. i know that cause i owned about 9 bmw there. the next thing is, buying a facelift model with low milage and everything i want in it its more expensive than rebuild my one and honestly you also will not know whats wrong with that one until you drive it for a while. so now comes the part where i need your help.

Im looking for someone who can refurbish bmw engines or a good place to find refurbished ones. I had a look in the internet for many hours know and you'll find them sure. the prices are from 2900 till 4000 but i couldn't read out if they are refurbished or not. I won't pay money for an engine with 180k miles when its not refurbished also to put one in with 70k miles without renewing when the engine is almost out makes no sense i think.

the other thing is, is it a very expensive or big deal to put the big air suspension in there instead of the already installed smaller version?

Thanks for your time, hope that thread will give good ideas and great discussions about. when i got all the informations i need and start with everything maybe in may i also would like to present a photo story about it