My X2C is setup as follows:
• ESC - Hobbywing 120amp (from eBay)
• Motor - Trinity 7.5t (from Telstar Racing)
• Servo - Savox 1256 (2nd hand from oOple)
• Cells - SMC 60c saddles (again from Telstar Racing)
Like Mattybucks says buy the best you can afford