hey donshl, thought someone else would have posted something for ya by now, but i personally haven't tried these, I'm sure with shock towers like FLM's, with 100 mounting positions you could use them. I always just buy the stuff and see for my self if i can get it to work or not, more times then none i come up with something, not sure of the exact length of the stock shocks, but i know the CEN shocks are shorter then stock, not by much maybe 3-4mm and they work for the most part.
Ok just researched and the stock hpi shocks are 165'ish mm (6.4"), those are 130mm (5.1") end to end, so they are only less than an inch smaller, i say go for it and give them a try, not a bad price, something i would do.
