Going from elec to gas, just woundering what servos best suit gas i.e higher speed or torque. Ive always used top range servos in elec but in gas it all needs turning down does this mean i only need slow servo's?

Yep, the slower and cheaper the better.

I run a futaba s3003 on my throttle, but i will never go back to a slow steering servo, i think my servo's delay atm is .09 sec on the steering, it makes me feel so much more intouch with the car. I highly suggest a quick servo on your steering.