I have a question...

They just clip in. What would be the advantage? We glue them on Tjets so we can keep the body a little lose.

I think that it may not matter much as well, but I do know that the general 'idea' is that the rear of the car would tend to try to go 'side to side' on launch from the tree, and that too much play with that guide turning from side to side can make the car leave the line slower, since it will be 'fishtailing'. At least that's why on larger scales you make the guide tighter on a drag car than you would on a 'road race' car. But, then again, on most larger scale tracks, braid is used instead of rails, as we do on most HO tracks, so the rails may actually limit the movement of the rearend of the car more than a 'flat' track using braids. I think it just might be something to think about.
And, yea, I've noticed that with the guides too. But, I only have one 4 gear guide pin, out of all that I have, that actually have a two sided pin (I have 10 complete chassis, 5 of them are older Aurora, and about 5 extra guides not in a chassis) . That's on one of the newer AW chassis that I recently bought. Haven't had to 'shave' any of them down yet for any proxy races, but that may have to do with a difference in plastic track over a routed mdf track. I think most guys when they route their own (or have them routed and built) tend to make the slots deeper. Yet another issue that may become a future problem if we do get more plastic tracks involved in our proxy races, or just races that others will run on their own schedules.
Ron

You are VERY correct. Definitely NOT anywhere near a Mean Green! The new AW arms that I have all ohm out at 14 to 17 ohms, with most being closer to 16. Mean Greens are rated at around 6 ohms (some of the 'original' Aurora versions with green wire actually can go as low as 5.5 ohms, altho I've NEVER been lucky enuff to find one of those..lol.) In case you weren't aware, there are two Mean Green versions. Green tip, green wire ('original' Aurora, were the very first ones made, generally considered the better of the two), and the green tip, gold wire versions. These were made by American Line, and are the most 'readily available'. Either one works good, altho the gold wire almost always ohms out just slightly higher (but still in the 6 ohm range). What you DO need to be aware of, when you mount a Mean Green in a newer AW chassis is to be sure the arm doesn't 'bind', or have too much play. There have been instances where the shaft holes on the chassis are smaller or larger, or the shaft size on the arm is different, and the height of the arm is taller than the AW chassis, causing binding. Pretty sure this happens mostly with the green wire versions, but I could be wrong.
If anyone else has more info, or has run into these probs please post it. I can't say from experience, as I pretty much haven't tried using a AW chassis with these mods yet. So far, all my chassis have been 'originals', except for my Rat Rods, which I've left the AW arms in.
Ron (Bondo)