Well I gave the car a bit of stick on the way up to the meet tonight on a B-road that I used to travel daily for over 8 years, and I noticed that the turn-in on the new settings was better than the prodrive settings I had previously. I think there is more of the contact patch of the tyre on the tarmac with the new settings, so even the slightest touch of the steering wheel seems to result in the car responding quicker than before.
It's worth noting that I did fit a front set of Toyo T1R's recently, replacing the T1S I had on there before (the inner shoulders on them wore out). So perhaps some of the difference was down to the new tyres. I've done very little mileage in the scoob since the start of December as i've been using the Mrs car (she's on maternity leave) so that in combination with the crappy winter weather means I never really got the chance to 'evaluate' the T1R's.
Unfortunately I never drove my car with the springs on & the geometry untouched so I don't know how much difference the springs alone made.
I'd recommend giving it a couple of weeks driving with the springs done, then maybe give Dunc a shout - it's only £55 after all, so it's not a fortune if you only notice a small improvement. It all depends how fast your hammering it I suppose.