I have driven both the losi G+ , ssg, bg, and cgm. I do like the cgm overall. I did have a problem with tweak but when I used the beveled screws on the shock tower I never had that problem again.

The Rayspeed conversion is still has a quite flexible chassis. Correct me if I'm wrong Randy, but I thought he was using two upper plates on his Rayspeed also for a stiffer chassis. The main difference between the Rayspeed and the SSG is that the Rayspeed moved the servo position 90 degrees (like the CGM) and the battery placement was slightly more towards the center and and a little more forward. The chassis was also a little stiffer than the SSG, but not by much.

One thing that is nice about the double deck cars is they are overall lighter which equals more speed, in theory. But tweak will always be an issue. That is the tradeoff. If you think your XXX-S needs a diet, you can use a dremel to lighten the chassis. Nevermind if you are good, make some cool designs on the center tunnel while losing weight. Plus if you don't do too much, you won't have to worry about tweaking the chassis. Kinwald, Hodge, Francis and a few other factory drivers have done this to theirs. The cars are in the XXX-S forum. Hodge's is on page 400, I think the others are a few pages back from that. Infact Randy's is on "the diet".

It also doesn't cost you $90-$145 to buy a new chassis/conversion. Unlike the CGM conversion or the Rayspeed conversion respectively. Another reason I chose the XXX-S.