Most of the lads in my CC are on bikes that cost more than my car, super light carbon frames Di2 gearing etc. They all have to pedal like crazy to keep up with me free wheeling on a decent downhill section, I've seen speeds in excess of 50mph before I've chickened out and applied the brakes, whats this super bike I'm on I hear you asking??? It's a £500
Halfords jobbie a called Carrera Vanquish, as others have said it's all about the person sat on the bike rather than the bike under them, you won't need to worry about the bike spec and saving a gram or two here and there until Sky phone you and ask you to stand in for wiggins.