SPOOL!!! i just love it... it allows you to late-break on turns which is sort of an advantage especially if you are being tailed by a one-way(er), it distracts his driving coz definitely he has to release throt earlier than you and some tend to forget that they have a different line than yours(one-way-ers). also, it gives you the advantage of being able to accelerate hard upon exiting a turn as Ben.C has mentioned. disadvantages however are minimal like understeer, but by adding anti-dive in the fronts that would sort it out. tire wear suffers more when using spool than using one-way... and belts too
with the Mi2 it isn't such a problem coz we use belts made by GATES
hope i'm right on this...