I am considering getting a BMW 60 M5 Valvetronic Exhaust System - Fi Exhaust for my beast. However, it wants a vacuum connection to operate the valves. What is the best place to pick up vacuum? Near the vacuum assist pump or elsewhere? Did anybody else do this? Or should I just go for Eisenmann mufflers and call it the day? I like the valve aspects to quiet it down a bit when needed.