12th newbie questions

[Timee80]

Thinking of having a go at 12th but need to know a few things first.
What chassis should i choose that will accept a lipo and be fairly easy to setup? (never going back to nimh cells now)
What range of tyres should i buy?
I have a 9650 low profile servo that i assume will do the job but only have larger sized esc's. Can i buy a bodyshell to allow for the extra height or do i need to invest more money in a slimmer esc?
What spares are essential to carry?
Anything else a newbie usually slips up on when starting out?
Any advice appreciated