Wiring questions s50 swap. Standalone, or OEM?

[Wild_and_wondeful_E30]

Hello everyone this is my first and most definitely not my last post on here. I am in the process of an S50/6sp out of a 95 m3 into my 84 318i. My e30 is a complete roller and I am currently finishing up the suspension and 5 lug swap. I am getting close to the point of dropping in the s50, I am currently trying to wrap my head around the wiring side of things. If my e30 roller had existing wiring it would be fairly straightforward as many guides exist on that topic. But as I previously stated the car is a completely stripped roller. My build will be for track/drift purposes so I'm trying to keep wiring to the minimum. I am at the point where I am looking into purchasing an OEM fuse box and body harness and retrofitting it, this seems like the best option if I want to retain OEM functionality. My question is should I continue on that route or is there an aftermarket standalone ECU and wiring that would simplify installation and help me get to the point of running my engine with the least amount of bottlenecks. I will appreciate any tips or advice on this subject, Thanks so much. Btw I am using a silver label dme currently. I was planning on buying a EWS delete chip. My brakes will custom with chase bays BBE, I want as much manual control over the car as possible, as it will be for track use.

[varg]

S50s in E30s are a very common swap, they're practically a bolt in at this point with the level of aftermarket available. For almost any situation not as common, standalone that uses a stock or premade harness will be easier than retrofitting a more modern OEM ECU because it isn't integrated into the other modules or security systems, but then you need a competent tuner. Once you get into doing custom wiring harnesses it's a wash because wiring is expensive.

My brakes will custom with chase bays BBE, I want as much manual control over the car as possible, as it will be for track use.

Is that that single circuit master cylinder kit they sell? If so, find another route. No car should be converted to a single circuit brake system, I would be surprised if they'd even let it pass tech since it would be negligent to let a car with no hydraulic redundancy on the track. Any time that kit is mentioned I am obligated to point out that the claim chase bays makes that the single circuit system is no more prone to failure than the OE system because of them both having one reservoir is a complete lie because stock systems are internally divided, and no automotive braking system in the last 50+ years has used a single circuit or single feed. You have to go all the way back to ancient stuff like early VW Type 1s to find single circuit brake systems, even a trabant has dual circuits and dual feeds.