I had a chance to test the 5 gear gearbox yesterday on medium grip astro. I didn't managed to back to back the change but it felt very nice to drive.

I started with my normal setup and added 0.5 rear toe to 3' and moved the battery back one hole. Good rotation but could do with a little more steering so moved the battery forward 1 hole - car was really good, good rear grip and felt much quicker rotating in the hairpins. Final change was to raise the front inner camber link 1mm to 4mm as the track had an off camber corner onto the main straight - this helped keep the power on and the front drifting wide, really nice.

The gearbox is nice, needs lots of thread lock as screwing metal into metal, need to check everything over.