I, uhh, can’t even…
V4 - please read the FAQ.
Superchargers - please read the FAQ, or watch some LDUs on the official YT Automation channel, or switch the game to open alpha and look around in it. Superchargers are coming, and, by Automation standards, very soon (they already are available in the open alpha).
Although I admit that the other suggestions don’t seem bad or repetitive. Actually, I’d like such engine filter too. When I want some 90s I4, I don’t want to have to scroll through 50s and 2000s I4s or 90s V8s and I6s too. As for the customisation, I can’t really picture what more would make sense to be customised, since I think the heads or their covers and the intake stuff are usually the things that “make” the engine’s look IRL.