The standard GTI is a belter and even a Stage 1 map will transform it. A Stage 1 GTI will give you similar power to he Eddy but for less ££££.
Clutch should be fine (on both) with a stage 1 map, some peeps do get slip on stage 1, some are fine on Stage 2+ with a standard clutch, a lot of it is down to the aggressiveness of the map and how you drive the car. Look at the linear maps, less aggressive.
As for he handling, add a Anti Lift Kit, engine mounts (at least the lower engine mount) and you'll be fine with getting the power down. Add some poly bushes to the front wishbone and a Rear Anti Roll Bar and your off.
Oh and "Is the Eddy worth the premium", yes. But I would say that!