Back amongst the automotive. Got a 300k mile e34 from my dad's friend. Vanos m50 and it's weirdly mint for being high as f*ck mileage. Guy's got a decent collection of cars, all of which he's restored (even the later bmw's) and know's what he's doing though so he kept it decent. Going to his shop and seeing his super bee, foxbody, Hudson, slammed c10, e39, and e61 wagon, and a couple more I'm forgetting was awesome.
And holy f*ck I can go over 35mph, f*ck that moped lmao. It's on KYB's and lowering springs right now but it just makes it look clapped out with the studs and steelies. I have plans for when I'm financialially sound but nothing insane. Mostly shaving weight where I can and getting suspension and chassis stuff sussed out. And a 5speed. Thankfully the Getrag 260 it needs was used in a decent bit of stuff.
Old friend of mine just LS swapped one of those. Wagon though.
It needs a getrag 260, but at the same time this m50 has like 320lk miles on the clock, so over the spring/summer I was gonna get a trans, hopefully 4.10 LSD, and a lower mileage m50 to do the 2.8L stroker build with an m54 crank and what not. Suspension is probably just gonna be H&R's on Bilsteins. It's on bavautos and kyb's right now and it's got just a bit too much body roll still.
Also there's that Hyde supercharger kit using a Toyota sc14. Finding a used charger and buying their schematics to have a machine shop build or just buying their full kit is something I wanna do further down the line. Kinda wanna make this a fun daily and eventually get an E36 for slippin n sliding.
I assure you that they are very fun dailies but a reason I sold mine was because it was slow and I didn't want to spend the money making it fast.
All the automatics should have 4.10s already so if you don't have one I'd be surprised. I don't know if I'd want a 4.10 with the 5 speed though. Mine was either a 3.46 or 3.64, can't remember, would have to Google it. I liked it. Most opt for the 3.93 (?) M5 diff. Obviously you want a LSD. I don't know about the American cars but the Canadian cars got the LSD with the Winter Package but that included stuff like heated seats which weren't available in the USA so I don't know how to help you locate one of those. Up here it's as simple as seeing if the car has heated seats and then you can be 90% sure it's got an LSD.
If you're doing a stroker build just use the engine you have. You're building it anyway. I definitely recommend some sort of forced induction though so I like your supercharger idea.
The stroker build would be on a new engine only because A. I'm worried about mileage but it doesn't really show much age at all and B. It's actually not as intensive of a stroker build since all of the displacement increase comes from the m54 crank and iirc the vast majority of the rest of the internals are reusable and makes like 260. Might do the supercharger kit first with an sc14 on like 5psi and then when I have the new engine, the kit works for Eaton m90 and newer 112's so I could build for more boost while it's out. Not sure on my ratio atm but it's definitely a one wheel peeler. Hoenstly that'll boil down to what I can get for cheaper at the time.
The only two things mileage naturally causes on an engine are bearing wear and piston ring/cylinder wall wear. Any engine build will involve new bearings and piston rings. Period. You're a desperate African farmer if you reuse those. Almost all engines will at least require a cylinder hone. Most people simply plan to replace the pistons with a .030" over bore on the cylinders. On a vehicle that old I think you're wasting your time looking for a low mileage engine to reuse a set of pistons. You don't necessarily need to buy fancy forged pistons. Cast pistons are available for actually quite reasonable amounts of money, and by doing this you can control your compression ratio a bit better. Without forged pistons though I'd limit how much you push your luck with increased boost and timing. I believe they're cast pistons from the factory anyway.
If you're doing a stroker do it once, do it right, and you will be fine. Replace rings and bearings and you may as well do oil pump, head studs and timing chains, it would suck to put a motor together only for the oil pump to shit itself (although that's more an M52 problem).
The guy who sold me the car has some ridiculous parts hookups that I'll never wrap my head around. Found me a set of oem wheels for 35 a wheel, with tires on em (probably shit but who cares)
Nah he knows employees at scrap yards all over, he himself is some sort of senior pilot for I think Alaskan. Not exactly the type to deal in hot parts.