I guess I'll throw my 2 cents in.
When I bought my slash, I went nuts on mods right away, I bought the ProLines and the extra spring kit, and a wide assortment of fluids to find something that worked well.
I only bash with the truck for now, but have been invited by a couple guys down at my LHS to try racing, so that may come in the near future. I don't know if I am doing something wrong, but IMO the super soft and soft springs are just too weak and just collapse under the weight of the Slash with a 3S battery installed. I tried multiple combinations of spring rates and fluid weights, and came to the conclusion I could have saved myself some money on the "coolness factor" by buying just plain old big bore shocks. I'm running matched spring rates on all 4 corners (Firm long and short springs, 50wt fluid on the rear - Medium long and short springs with 40wt fluid on the front).
IMO The whole dual spring set up is a huge gimmic (hey, it looks cool right?!), I did hours of research watching youtube videos on peoples setups, reading tips and trick on the pro line site, asking questions on the traxxas site, before trial and error (and a few bottles of shock fluid) finally led me to the setup I have now.
*EDIT*
Sorry, I will say they're not all bad, but for the price, the GTR shocks look to be a better deal with less hassle. The PL shocks are extremely beefy, nice big shafts, big reservoirs, relatively easy to change the fluid in (although one of my caps mounting holes was a tad too small and had to drill it out just to get the screw in), that was relatively minor. If you do get them, make sure all the O-Ring seals are seated correctly, I had one leak out a lot of oil because the bottom o-ring wasn't seated in it's little space.
(Last edited by mezzio : 1.01.13 at 12:22 am)
*Land* Slash 4x4 | Kyosho DRX VE
*Air* Blade mCP X BL |Blade Nano CP |1SQ Quadcopter | V911