Get down to your local club to see what they are racing.
Go for a good, modern 12 volt charger - make sure its suitable for nimh, your IB4200's will need regular charging/discharging & equalising even if you are not racing.
You would manage with 27mhz, the servo (same servo for 27/40 or speky has to suit speedo not trany)may need upgrading, faster/stronger - bluebird seem good value.
The motors seem a bit pokey to me, possibly start with higher numbers or a "stock" motor.
and get down to where you are going to race and see whats required.
