Seems we've been missing out. We're not too late to the party, are we?
Lots of questions in here. We'll try to get to them all over time, but please don't hesitate to remind me of questions already posted, or ask new ones.
We think check valves are absolutely necessary. We don't sell a kit without it, and it is included in the price.
The VTA kit actually has a check valve in it, too! It's designed so you can't pull air through the VTA filter into the intake.
Thanks for including us on the list. Hope to be around more.