After looking at the truck I see now it is not an LN2, MB has some crazy numbering. One thing, if your future plans include travelling to other countries outside of North America (ours does), go with the MB. If you plan on sticking to North America think about a F550, Ram 5500 or a 4wd Kodiak. Different build but will be better suited to American roads and have better parts support.
The engine this truck has is the latter generation OM366LA, it was used in marine use up to 300hp. Not sure I would push it that hard but there are companies that will do it for you in Europe. One thing that is hard about suspension changes this early is to dial it in you really need to know the final weights. Pretty sure this truck will weigh more as a bare chassis than ours (we have an LN2). Which brings up weight, these trucks are not overly powerful compared to American trucks. We went with a full composite box in an effort to keep the weight down (and be very well insulated). Currently we are right around 20,000lbs, it would be at least 1k less if we didn't have the motorcycle and lift. If possible I would try to keep that close to your final weight, but might be challenging depending on the build. From my understanding (I am definitely no expert) is the OM366 came in the "A" and "LA" variants. The "A" version is 170hp and lacks the intercooler but can be boosted to about 200hp. The LA's all have intercoolers and are either 200 or 240hp. The 200hp was the earlier one. Since these engines were also used in UniMogs and marine use, and share a lot of parts with the OM352 you can source some engine parts in the USA. So, try and build with final weight in mind. It will make accelerating (hard to call it that in these trucks) and climbing hills better. I am hoping the turbo swap will let me move out of the loaded semi truck lane in the hills. As far as hp, we have travelled with a truck with the OM352A (170hp) and I can say we go up hills easier.
Also for the best information on that specific truck, search eBay for "Mercedes EPC" and download/install to a Windows PC. Once installed plug the VIN in and you will have the original build specs, along with parts and service manual. Best money (very little money) I have spent on the truck. These are pretty basic machines but do require some specialized tools depending on what you are doing. If you have previously worked on engines you can probably work on this one.
The parabolic springs are from
DFF. THE FEATHER EXPERT. - START (federfachmann.de) , if/when you get to that point let Harald know we have talked. He can also supply the shocks from
Heavy duty shock absorbers for Expedition vehicles (marquartshockabsorbers.com) . They work together to dial in the specs needed. With the original springs we would cringe even at the smallest bump, now we can do 30mph over corrugated roads. We did find after the upgrade that the shocks could not cope with these more active springs, so now the upgraded shocks are on the way. Hard to specify the spacer blocks this early as you don't have the corner weights to level the truck out. Harald can also supply those along with the U bolts.
I am not sure about the auto transmission but would assume the final gear is direct drive. At least on the LN2 trucks there wasn't a transmission with overdrive available in the 4WD versions. With firetruck spec truck (the AF versions), a lot of times they came with the faster ring/pinion in the axles. A search in the EPC will tell you which ratio this truck was built with. Ours came with the faster axles, but there is one more faster but it is about $6-7k in parts alone, then you need a special tool to swap them out. Not something I dare to try.
For the rims, it is good that the truck is 10 bolt. Will make it easier to source them in the USA.