Ok, so here is the dealio... I have an old Planet-X DirtJumper/Slalom frame that I wanna build up for two reasons. First of all, it will be a DJ bike for me when I take my kid (6 yr old) to the local track. Then, in a few years, I wanna give it over to my son as his general MTB. The bike has something like a 20.5in ETT and 26in wheels so this is about the smallest MTB that he could fit on. The only outstanding item I have is what fork to put on it. There aren't many 26in 1 1/8 steerer-tube forks out there w/ a 20mm axle. Right now I have it narrowed down to the following: Manitou Circus (100mm) It comes with a HARD spring, but I have a line on a soft spring that I can put in the fork when I hand it over to him. The other option is a used RockShox Argyle RCT. Its a 140mm Air w/ spacers to take it down to 80mm if needed. So which fork and why?