Ah, so my previous was the original 2002 Spyder CC, so a huge difference in the chassis etc. The CC is way more sorted on the GS and makes it much better to drive. It's possible the chassis stuff was sorted to a similar level on your car, Andy. I've driven a manual post face-lift and loved it for heel&toe, but still feel the GS feels better. I also am half-and-half about the interior - I did love the luxury of the 4200 version compared to the sporty nature of the GS, but that seems to suit the nature of the car itself as well.
When it comes to the reaction of other people to the car, I have to see I was shocked at the difference. Both Ilaria was and Myfanwy is black, so not too different looking, but the GS stance just seems to grab attention in a very loving way. Maybe the Larini H-pipe and decats help, but that doesn't account for the attention the GS gets when parked.