Thanks for the mention, was good to meet you the other day and I'm really glad you're pleased with the installation. I can see you're getting some good advice coming in on the setup! Looks like you've got the itch now though....
Just to add my view to the thread, I was genuinely surprised with the 'base systems' leap in sound quality and volume with just the MS8 and addition of the centre channel. Given the fact you say it's only gotten better with a bit of tweaking you must be pretty chuffed!
As a side note, just to reassure you, I do get an 'occasional' pop on mine on startup when listening to music. Not every time though and certainly not at any level which I'd worry about. The only time I notice it is when the stop/start function has actiated. I had thought it was my JBL amp but after reading this and a quick google search, it looks like it could be an MS8 characteristic instead!