Certainly fitting out would be a lot cheaper:

OS 91 FX at £150 - or cheaper if going used or a cheaper make
4 Good servos at £30 each = £120

Depending on the price of the kit, you could get a decent performance for £500 - £600. For the C140, you are really looking at £1000+, though if really scrimping, I think you could get it down to £800, but then you are likely to start affecting performance.