Motor/esc upgrade help needed!!!

[Makaveli1512]

Hi there,
I am looking to upgrade my B4.1 motor & esc to get some more speed for indoor club racing. I have been advised by somebody at the club that sensored is the way forward??? I'm just not sure what to buy, there's soooo much choice even in the combo sets & I don't want to end up with something that I'm going to want to change again in a couple of months time!!! That said I don't want to spend a fortune either!!!! Maybe if we said about £200 as a top budget?!?!
Any advice would be greatly appreciated!!