I used Progressive Suspension fork springs on my scrambler. They are longer than the stock or Hagon springs and a little shorter than the Ikons. I used the P/N for the Bonneville (Progressive # 11-1126). By the way, the scrambler and Bonnie use the same OEM spring, just different spacer length.
The Progressives work great and they cost substantially less than the Hagons or Ikons ($79.95 retail, you should be able to get them for $60-70 delivered from some of the online sources).
I used the Ikons front and rear and the ride is noticeably better than stock. I think the fork springs made more difference than the shock swap...not sure exactly why.
Ikon fork springs are a little shorter than the stock+spacer combination. I used a PVC pipe coupler for 1" pipe, cut in half (across the diameter, smart guy). That was about an inch of spacer; I fine-tuned it with the preload adjusters. You will need a spacer with the Ikons on a Thruxton.
I wouldn't worry much about the price diffs...if doing both ends I'd stay with one manufacturer on the hopeful assumption that they actually design them to work well together.
A forum community dedicated to Triumph Motorcycle owners and enthusiasts. Come join the discussion about performance, racing, cafe racers, bobbers, riding, modifications, troubleshooting, maintenance, and more!