I have had a few trys on 7's over the years and sadly due to my weight I could bottom them at will
I can't remember all the names but the first set I tried were the heavier set of the R's/X's and they went back to the dealer as he had said they were suitable for my weight and when he saw me bottom them he gave me a refund
I then has a go on the next spring they bought out (don't remember the name ) Clive had bought them and was finding them a bit dead
I must say they were a step back and very unresponsive
I understand they have bought out another spring but didn't bother to try as a mate who it a very good bocker and has a spring breaking tendancy said he bottomed them at will
Older PJ springs were always a bit faster feeling to me and I prefer that also they were higher weights
The new Exo springs that I have had (2 pairs) have been the best springs I have ever used
So to sum up I have used both and at the moment I feel that the Exo's are a much better stilt and spring all round
Jason