I really don't think that big HP is all that important, unless you're running massive tires. At least in URE, there's nowhere your speed will get over about 25 mph.
Based on my experience, it's all about the suspension - you want it stiff (not hard) bw/ plenty of room for clearance, and good shocks. Too flexy and you'll be bouncing all over the place.
I just had 2" coil spacers and lift blocks on stock 19 y/o parts (cherokee). I didn't post the fastest time, but wasn't poking by any means... and the ride didn't jar too badly. Biggest problem (as evidenced by my crunched tranny line and self-clearanced rear fenders and chewed up tires) was not having enoug hroom for uptravel on landings.
FWIW teh clearance needed when jsacking up a wheel in your driveway is nothing like what you need coming off a 3' hump at speed. Technically the bumpstops (19 y/o ones) should have stopped it before teh control arm hit the top and crunched my lines. Guess gravity had its own plans, lol.
IMO, at least w/ thsi course, it's only at MOST 50% in teh vehicle. The rest is in driving ability... and concern for the vehicle. Lets face it, based on te hstats thus far, the best predictor of timing/success is not driving the vehicle home.