On the "performance" side of things, I committed blatant sacrilege by throwing on some intake mods.
First was a Bevinsee intake air scoop off Aliexpress. Wouldn't usually go for such things but it looked tidy, all black, no logos and supposedly helps with intake air flow and reduces intake temperatures by a few degrees so was worth a shot for the low price.
The second was a Dinan airbox. I've heard of them mentioned over on the E46 fanatics forums, supposedly being one of the few intake mods that are somewhat of an improvement on the stock setup. I'd never be able to justify the price of it though so never crossed my mind actually getting one. I happened to be chatting to @Eagle one day when he mentioned coming into possession of one as a bundle deal on his recent purchase. He didn't feel like using it himself so kindly passed it on. Absolute legend.
It's essentially just a different lid for the bottom part of a stock intake with a bigger filter fitted inside. Originally would have come with extra tubing which taps into the brake duct and drills into the bottom of the airbox, adding a third source of airflow. Unfortunately it didn't have that tubing intact but it's something I can just whip up as a DIY at a later point.
The filter is an odd shape but the filter elements themselves look identical to the washable K&N filters. Supposedly these aren't washable and need to be replaced every 1-2 years. Unfortunately, replacement filters are stupid expensive, are out of stock in most places and the few places that do stock them don't ship to NZ. I dug around the forums a bit and found reports of people washing and oiling them with K&N kits for years without trouble though so that's what I did.
Having taken it on one proper drive so far, the sucky noises do sound more pronounced, which isn't something I ever felt the need for but nice to have I guess. Whether it does anything beyond that in terms of performance, who knows. Does look cool though.
I did discover a few new issues on the first drive post paint correction. The first one being a massive puddle that started forming right after parking up.
The mind straight away jumped to the worst case scenario. Luckily, it needn't have.
Windshield washer fluid.
I had just refilled the reservoir as well. Didn't seem to leak when stationary but once the engine gets warm the fluid bubbling up and pissing out straight out the nozzles. Real weird one. Having talked to @Eagle about it he mentioned there's certain brands of washer fluid that are known to wear out the seals in the nozzles. Pretty annoying but what can you do. Will throw a pair of new nozzles onto my next order and will do some research on BMW-safe washer fluids.
The second issue could also have been more serious but ended up being a simple solution. I'd intermittently get a trifecta of ABS-brake lights pop up on the dash, maybe once or twice a year. Usually happened after the car had been on jack stands so I didn't think much of it. You'd restart the car and the issue would stay away for another number of months. This time around in the span of 2 days and 200-something km's it must have happened a good 25 times. Something more serious was at play. Got so annoying I ended up killing the engine without stopping and restarting again on longer straights.
Initially thought it must be a bad wheel speed sensor - some of the last components I've yet to replace - but having checked live data mid drive they were all returning the same numbers. Dug a bit into the engine bay having gotten home and discovered the positive terminal next to the ABS unit heavily oxidised and looking yucky. Cleaned it up with some wire brushes and contact cleaner, another 200km later and the issue is yet to return. Great success.