Rocket Valve and the Low Blow bolt are both designed to lower the operating pressure of your marker. The Rocket Valve can only be used at 400 psi or lower. Any higher than that and you'll ruin the valve. My first suggestion is go to Otter's site and read about converting your Spyder to LP.
Otter's Spyder Pages
: that is everything you'll ever need to know about Spyders.
If you decide to do an LP conversion then I would definitely use HPA instead of co2. I would also go with a Palmers or CP reg if you use HPA and do the LP conversion. If you decide to stick with co2 or not do any other upgrades go with the Palmers, its probably the best reg to use with co2. The BL Torpedo is pretty good too, I've never really heard much about the Detonator.