I know this is an old video, but to anyone that has an N54 (especially the configuration in the 335i), one of the best mods/upgrades you can do that will ACTUALLY help put down more power in the future is the inlet ducting. Those intake tubes pancake down at the firewall and core support between the filters and the turbos. They also soak up a lot of heat with how they're routed and are a lot longer than need be. On my old 335i, I got a drop-in (which is pretty loosely used if you've looked at how/where the inlet pipes are placed) dual short-ram intake setup that put the filters just behind the passenger headlight. After the tune for that intake setup alone I saw an extra 25-30hp. Stack that with a 3.25" straight-piped turbo-back exhaust (with cat delete pipes), intercooler & piping, higher rate fuel system, upgraded turbo charge wheels, stage 1 cams, and a larger set of oil & water coolers, I was pushing up near the 500hp mark. Much more than that and I would have started needing to rebuild the head and upgrading the transmission. Sure, BOVs are dope, but they don't do much of anything of significance aside from _MAYBE_ preventing a bit of conpressor surge (which is/was a totally overblown consideration.) But those inlet pipes SUUUUUUCK.
That all makes sense when like me you've seen guys turn an e36 328 into a 1000hp+ monster with some junkyard turbo parts. BMW has long had a reputation for over building engines, look to the M10 F1 as en example, they took 100k miles + four banger blocks, rebuilt them into 1400hp+ turbo F1 engines, the most powerful ever to see the track, from passenger cars. Yes, they were wringing 300HP PER CYLINDER in a straight 4 decades ago. Biggest problem was when it's massive turbo spooled, the engine output slammed from like 200hp to 1200hp and it was suicidal on a F1 track, but still.
I had purchased a forged one on my e90 the blow off sound would not activate. I cracked it open and the spring was stuck lol I now have a hks on my e92 and I like it obviously the higher the rpm the higher the blow off sound
