I've owed a B4.1 RTR for about a year now, its a good car. Very easy to set up, drive and it strong! Been racing it for almost a year after a 20 year absence form the hobby. I find the electronics fine at the moment more than enough power and speed.
ESC manual
http://www.teamassociated.com/parts/details/29141/
I use 5% drag brake indoor on carpet and 2.5% if its a little slippy outdoor.
max punch on carpet and std on astro/grass.
no reverse
The servo that comes with it is poor (weak and slow). I bought an Alturn AAS-752MG £22 ish very impressive for the price made all the difference to the steering, single best upgrade to the car easy!
As said above Schumacher Yellow minispikes all round should give you tons of steering but if your on mostly carpet then maybe yellow mini pins all round.
One thing to look out for on the B4.1 RTR is to check if you gear diff is correctly shimmed. Hold the spur gear and rotate one wheel, it should feel as smooth as butter. If not and feels 'coggy' its not shimmed right and may slip internally casing a horrible loud clicking under hard acceleration. I had to place all my shims inside the diff to solve this as i have an older B4.1, AE apparently know about this (bad batch of shims) and may have sorted it by now.
I think you should just stick with the B4 for now, parts are easy to get hold of and cheap! Learn as much as you can about setting it up and race it as often as possible!