I have a slider in mine, old type.
No issues with leaks-ever, but unless the latch is locked, it whistles.
You can open it 1/4 inch or lock it and the whistle stops.
But when you open it, even with the side windows raised, (I don't have winged vents), it cools off the cab very well.
Looks like a good source for an upgrade that is well worth the investment.
Wayne