I'm going to be moving to Pittsburgh from Chicago in August. It just so happens I'm going to be living two blocks from Frick Park, so it's time I finally got a mountain bike (currently a cat 3 road racer). My question: for the terrain in Frick Park, should I be looking at hardtails or full suspension bikes? I'd like to race eventually, and I know hardtails are generally preferred by XC racers because of their weight. But then again, I've heard that Frick has some pretty serious downhill sections, and I also have a history of lower back problems. Any thoughts? What do you ride in Frick?