Thanks for the reply. I guess I'm more bench racing than asking anything. I like the technical side of things I get into, so using roll out and things interest me. So I was just curious what is viewed as a drastic change. 2mm in the rollout, or is 10mm in the rollout drastic. Doesn't matter, I know I don't make sense a lot. So I'd say with my 106 rollout I'm right next door to the ballpark you stated. I ran a 104 the week before and felt my car didn't have the speed compared to the others. Wasn't the case when I bumped up a pinion, (104 to 106). I will go measure my axle right now. It shouldn't be crazy narrow, it's built as per the crc manual. I downloaded that and found the guy I bought it from had the left hub on backwards so it was 3mm wider on the left side than the right. Handled much better after fixing that I don't plan on cutting tires to reach a rollout, it was just a question trying to figure out what's a drastic change or a small un-noticeable change in rollout numbers. Thanks for taking the time to write, I can drive the cars decent, great with offroad setup, just trying to lean the carpet ways now too

The trackstar motors.. they aren't the fastest things in the world but they can take heat and keep on turning lap after lap after lap. I've got a spreadsheet with 2000 timed laps from this summer, the majority ran with the same 6.5 motor. It's on it's third set of avid bearings, and that thing has been phenomenal for a budget racer.