6s vs. 4s?

[georgec]

Thanks, I'm trying to come up with ammo to present to the track owners witch have adopted the ROAR 4s rule, but I believe can be swayed if I can prove to them that the only advantage to 6s is efficiency! I'm also on the hunt for a lower kv motor, and so far I have looked at the Tekin 1400kv that is priced at around $150.00 and the CC 1600kv priced at well over $200.00 Last night I came across another motor that Castle is carrying it's their NEU/MR 036/060/1300V5 priced at $119.00 makes it the most affordable. But if I'm reading the #s correctly this motor is only 36mm x 60mm and that seems small for racing. Has anyone here had any experience with these?