Not true? Try telling that to some UE forum member's who did twist the 6 spyder housing. It take's some power to do, but it isn't as strong as the 8 spyder's, thus for the difference in money you'd be better off with the 8 spyder's.
I'm not lying here...
Also there are better gear's availeble for the 6 spyder's, don't know if these will fit the 8 spyder's too.
http://www2.towerhobbies.com/cgi-bin...?&I=LXCWK1&P=7