Hi,
I don't have an M05 any more but I really got to grips with mine and had great results locally at our indoor winter championships.
A resource for you -
http://rc-mini.net/joomla/index.php?...=23&Itemid=148 - this is a race setup from Brad Portelli down in Australia, and it's fantastic, Brad really knows his Minis.
Also, Dave Allen from Bristol has a
great blog to which he contributes articles on the M05 - he's a very experienced and skilled racer and has a very good ability to nail good setups on his cars.
Tyres and diffs play a massive part in traction issues on the Mini. Sweep 25s and 33s work very well - try pre-glued 25s on the rear and 33s on the front, or 25s all round if you're a very very good driver. With the diff, the more it slips, the less it will act like an axle off power. So a slipping diff will cause off-power oversteer and make your car very nervous on corner entry. The best diff to use is the 3Racing oil-filled gear diff (part no M06-06) with 5000wt diff oil (filled to just above the small shafts connected the small bevel gears in the diff). This diff is great and gives an amazing amount of drive, needs servicing probably every 3 months or so with regular use.
Other things to look at for your traction issues are:
1) Are your wheels or rear axles buckled or bent? Spin the rear wheels, if they wobble then either your wheel is buckled or the axle is bent. Change the wheel and try again, if it's still wobbling, your axle is probably bent.
2) Take the shock off and let the wishbone hang down. Does it fall under it's own weight or is it stiff to move? If it's stiff to move then your suspension won't work as intended. Take it apart and work out what's making it stiff to move.
3) What tyres are you using? Are they old?
4) The M05 suffers quite a lot from the front end 'pitching' when cornering hard, leading to either traction roll or snap oversteer. The #54236 front shock stay helps to get over this, as does a decent set of shocks like the Tamiya M-Chassis Option Aluminium shock set.
That should be enough to help.
Joe