...will it accelerate from 40mph to 100 mph allot quicker...
Yes, it should be much quicker... it will not be traction limited at those speeds.
does power come in sooner so if your on bends giving it sum
I doubt it but you may need to be more careful with the throttle... the same throttle opening will, more than likely, result in more power than without the tuning box
you can brake and accelerate hard and feel that your on a laptime
Are you panning to track the car? The tuning box will not have any effect on the braking capability of the car, although you should, perhaps, consider a brake upgrade... If you cannot feel the effect of 35-50bhp then I'd be very surprised...
.,...
seen figures increase in bhp of 35/50bhp which is alot, torque gains
It is a significant increase. So consider the extra costs - if you make use of all the extra power - reduced brake life, reduced clutch life, reduced tyre life, significantly increased insurance (probably), effect on warranty if VW found out... etc. etc.