Just to add to the forum knowledge!!
I fitted the STR.T shocks to the back of my 2009 100HP this week - absolute night and day. For 40 quid a shock you can't go wrong. From what I read and hear, the STR.Ts are around a 3 on the 1-10 scale (10 being stiffest) of the KONI SPORT (yellow) shock adjustment range (can anyone confirm?), and as this seems to be where most people have the SPORTS set (if on the rear of the car), I can't see why you'd spend the extra on a car as simple and rough as a Panda!!
People have written they make the ride firmer but less pogo-ing - I disagree. They just make the ride better. If you want to know how it feels, put a couple of average people in the back on standard shocks and go for a drive! The extra composure at speed is massive - so, SO much better. And at low to mid speed, it just feels like the suspension is working properly! Bumps, potholes, bad surfaces are all taken care of much more efficiently. It feels like a car should.
What I can't say is whether it really makes a difference to the way the car handles. You can go faster and enjoy the speed more for sure, but only because the car stays in control of its movements for longer. In corners, at speed, I don't think it really makes the car feel any different. You just have a car that rides better, and as a result becomes more enjoyable, but don't expect the massive changes in "handling" (whatever people mean by that) some people suggest.
I definitely notice the front feels less "expensive" in comparison now though. The front and back and much more in tune with each other, but the ride at the front is noticeably rougher. Less tight is how I'd describe it. I think if I were to change the front shocks I'd spend a bit more and go for the SPORTS, just so I could get that extra range of adjustment...
Anyway, just my experiences!
C