I had one of the 1400's too. Pity Suzuki didn't spent some money like Yam did it their XJR1300 equivalent to keep it in the Dogalogue.
It was excellent handling grunty bike and well liked by many here.
That bike is very smooth from memory and the feeling that Suzuki wanted for the GSXS was a more busy race bike motor reflecting that something would happen once you twist the throttle. A caged animal just waiting to spring - so you should realise you buying into a different sensation with the GSXS1K.
The GSXS750 motor is more like the 1400 in character, but is nowhere as powerful in acceleration time (GSXS1000 or 1400), but handles very well all the same.
Perhaps a test ride on a 750 would be a worthwhile trip if you can find a demo in WA and save a few Dollars ? I ridden one and it is different to the 1000, not just scaled down, more a softer bike as against hard edged. In the 3 Bears, the 750 is Teenager Baby Bear, the 1000 Mummy Bear who likes the dance floor and the GSXR1000 is a growling Daddy Bear.