I suspect that the E46 hasn't been supercharged all that much and so you risk finding yourself in a situation where you've hit an issue and either you're the first or nobody has documented their solution to that particular problem. I had something similar to this in that I was one of the first people to SC a MK2 with ABS, so the "common" intake pipework design just could not possibly fit. Others had been there before me but nobody had written up how they did it - so I wasted a LOT of money on silicone hoses until I found a solution that worked well both on paper and in the car.
There are quite a few supercharged E46 M3's with pretty much bolt on kits available for them. The engine layouts and ancilliaries are fairly common between models and ESS seem to have some experience, since they do the E46 M3 kits..