Sorry, you will NOT get the same mpg, maybe when you've clocked 15/20k miles. I've had 3 Clio sports ok only up to the 182 in the past and it's all down to weight. And if I know Clio drivers like myself you will not be very light footed. Just saying. The Golf GTI is a way better car overall.
I didn't go keyless and don't regret it. Blimey at least you have some control! That's without the theft fear, every time you park up, go into pub/restaurant with keys and guy on next table or at the bar has laptop!Let alone foil lined crisp bags. Save your cash for several fill-ups mate.