dude yeah the RG500 was / is awesome too. I nearly brought one of those aswell a while back. i'd still be keen to get my hands on one.
I orginally brought the RGV250 to do a 500 conversion on which guys are making pipes and parts to make the conversion pretty simple. That would be a cool set up. easy 1hp for every 1kg. But the GTR came along so i've canned that for the time being. There will be a few hot RG500 motors getting around now to, most of the speedway mini sprint cars that used to run the 500 motor have now switched to "diesels".
I think the RZ was also nick named the widow maker, certainly not many of em around any more, all been crashed. I've high sided and low sided one of mine. Yeah brakes and suspension is shit. One of mine has a FZR1000 swing arm conversion and also an R1 front end.
The other one has an RGV front end.
The yanks shit bricks over the RG and RZ or RD as it was called in Europe as they were never allowed 2 strokes because of emmission laws. There are a few nice ones in the US, brought in as "parts" from Canada and re assembled.