Hey Walt, I like the PN Gear Diffs quite a bit. They are smooth, quiet, quick and pretty easy to change spur gears on. Easy to clean with just a quick spray of electronics spray, then lube bearings and tiny dab on the spider gear pins. Their down sides, or at least what I have found, are you can't loosen them to allow slipping like you can with Ball Diffs, tiny parts (spider gears, pins) are expensive and rarely instock and if the tension nut loosens in a run they can strip. Luckily I haven't had it happen, alot in part of using blue thread lock on the tension nut. I have 2, 1 on my RM chassis and 1 on my Stock chassis. I run a PN Ball Diff on my ProStock chassis so I can set the slip to reduce power on take off. On the Ball diffs you get a slight bit of wobble of the Spur Gear because of the design which makes them a bit more noisy. Not a big deal unless the Wife is sleeping in the next room!

And my first MR03 ReadySet quickly went from BoxStock to Stock from me adding parts to help with control. Which was a big help learning this scale, disk damper being the most helpful. I went to a PN 70T pretty quickly after that. They really aren't that much faster, but have TONS more torque. Which makes you get to speed faster, but is A LOT to control. It puts you into the wall before you know it, but to combat this you can jump to a larger pinion, turn down the throttle D/R. For me BoxStock really became fun to drive after learning on a Stock chassis that was easier to control.