The X flow will drink petrol (25mpg will be a dream), but will be more powerful than the VX. VX will be ok, but less power and not much scope for getting more power. Just my 10 penneth, but personally I'd look for a K series.
I run a 1600 VX engined car- Torque is better than the Ford but a 165bhp tuned ford will be much quicker. The vauxhall engine is generally tougher but somewhat difficult to tune up (as already mentioned). Both will do sub-28MPG and both will sound glorious.
165 bhp from a crossflow won't be very flexible. The crossflows I've driven with 120- 135bhp have been great for road use, but 155+ makes the engine very peaky.
The K series would be my choice for light weight and fuel economy.
