Motor buying help.

[Burty248]

Hello im a looking for a new motor fo my associated b4. I currently have a tamiya sport tuned 540 brushed motor and i am looking for somthing faster but still cheep, under around £20 to play with. Also i have a tamiya tfu-101bk esc and i dont wanna replace this if i can get away with it. Bonus for those who give me the specs on my current motor and explains the "T" and rpm so that i understand what i am buying , im a bit of a noob. Thanks.