There are/were guys saying there diff (rear mostly) felt like there was no oil. 50/30 was recommended by some of the local racers. The manual (at least the current one on page 23) says there is 50k in the front and 30k in the rear, so I was going to leave it as-is since my new Rally definitely felt heavier up front than rear, but the rear did not feel empty. Since I had the car torn down anyway for modifications, I figured, I should be sure. I open the front diff. There was thick oil inside, but was half filled at best. I wiped out the majority and filled it with some new 50k. It was a huge difference. It's way heavier action now... like 2X heavier. This just adds again to why I prefer kits over RTRs.