I would strongly urge you to follow the advice given. I have installed many versions of their 💩 kits in different make vehicle and have yet to find one that is much different than stated. Bergman sounds like he's dialed in what they haven't.
On the hiss PD mentioned might try a different fluid. I had one that we likely tried 5-7 different fliuds in to get ring of a low RPM noise. Lucas was the best, it waas still there a bit but the customer was OK with it (Thankfully)