Best B4 Beginner Motor and ESC?

[Shorty]

Looking to get into off road racing. I want my electrics to be easy to driveto start with but not need replacing straight away as my experience grows so...

If I get myself a used B4, should I replicate the RTR motor and ESC...

(The RTR has a 3300kv Reedy motor and an XP SC 450-BL ESC)

or go for one of the other options Reedy do? There is also a 3900kv, 1900kv and a 6100kv, all the same price at £102.

What effect will these other motors have, faster, but harder to drive in terms of top speed and my reactions!

How come these Reedys aren't given a Turn T rating like 9.5T, 10.5T etc?

Any other smooth performing, beginner ESC and Motor combos I could look at for the same price or preferably a bit less!