The gears that come in the kit are straight cut also. Tooth count looks to be the same. Not sure whats really different except the pinion appears to be ground on the bearing surfaces. Maybe jut a higher quality gear set??? Not sure why though because the stock gears have been just fine.

I wouldn't mind seeing an optional set of gears to allow over-drive on the front diff or under-drive on the rear diff. I always loved that option on my xray and mugen cars. Really made the car drive great on low grip tracks.