get an ezrun mate, by far the best bang for buck out there, the 18t motor clocks in @ 5400kv,
http://cgi.ebay.co.uk/EzRUN-18T-brus...#ht_4315wt_939
pinions are easily available on ebay, i'd start off with 13 or 14 tooth with the stock 45t spur gear, which was easily fast enough when i was running this system a few months ago.
http://www.tracksidespares.co.uk/pro...oducts_id=1308