People on here are making the black run / whytes sound like some uber DH death trail. Seriously its not too bad, no mandatory air or drop offs, a few steep berms on the black section and rock sections on the final descent of Whytes. Its all rollable and not too nasty at all. If you do go too fast theres a danger of unexpected air off a few tabletops on the energy section, but again ride within yourself and you'll be fine.
Biggest dangers will be your bike failing if the bars or stem are already fatigued as it is rough, or your cantis loosing power on sections due to cable stretch (assuming they were set up ok to start with).
Sorry but you WILL be slower than some on FS bikes as you can get away with more and carry speed easier with a sprung bike, try to keep your ears open and get out out way of people on a charge to avoid aggro. You will be limited to how well you can 'ride light' over stuff, pick your line and how much punishment your arms and legs want to take, but there no reason to be too slow other than fear!
Drop your saddle, try to get some fat tyres, set your cantis up well and maybee a shorter stem (heresy I know) and let it flow!
