I had the same spring rate as you. I changed to a 300lb spring in the back last month and it's a much more enjoyable ride. The fronts seem good, but the back was giving me a beating. Here's a link for a 300lb red spring. search.html?q=EIB 1400-250-0300 The site has many options for springs
The 300lb spring is what DDM shocks use as well. When I was placing my order I asked about the spring rates and was told they use 225 front and 300 for the rear.