help with my new pred

[jamidumix]

hey all, ive been a ling time viewer but this is my first post. Its all been very informative so far but i have a few more questions.
(Actually I have been hanging around just looking for a couple of years now!)

I just bought a new in box x10 and ive built it all up following the appropriate tips and guides here on oople and over at the-pred.co.uk, and everything seems to be cool. i havent put any electrics in yet as they are still in my Durga and im dreading having to make my own saddle packs but im gonna have to get around to it at sometime I have seen people using hex bolt wheel adapters and I wanna do the same. I have seen the guides for doing this but they dot seem to mention what siza I should be looking for. I have seen 4mm 5mm and 6mm sizes available from Tamiya and Kyosho and Square etc... Which ones should I go for? I have some 5 spoke HPI wheels that I used to run on my Top-Force that im sure what look incredible on the Pred. speaking of which, the wheels are the wider size all ound (kinda like the old Manta Rays etc) I was wondering if this would work on the Pred and if so what is the benefits and/or dissadvantages of using wide tyres all round? I would of thought more tyre surface in contact with the ground = higher grip. At the cost of extra drag I guess.
I should also mention the guys I race with arent so serious about strict rules at the club. We all use 23turn motors and thats the only rule. (I live in Japan by the way) Anyway what I mean is im not concerned about the wheeltrack becoming a little wider or whatnot.
Im looking forward to flying the British flag here in Japan with my pred and im hoping everyone here will help me kick copious amounts of Tamiya. Yokomo, and Kyosho arse
Cheers.......