This isn't your usual wire bead vs folding question, I realise whenever anyone asks folding always comes out better.
Not necessarily: there are two main features where wire bead wins:
- Wire bead is somewhat easier to install, especially if the tires are a tight fit on the rim, because it stays round during installation, but with loose rims or rims with a deep center channel, it isn't hard to install folding bead either
- Wire bead is far cheaper
About the only benefit of folding bead is that you have the ability to easily carry a folding bead spare tire on long tours. In other situations than long tours, carrying a spare tire doesn't make sense.
changing to the Gatorskin as make the road so much smoother.
I used to have Gatorskins. I changed to Grand Prix 5000. This change made the ride far smoother. I suspect the cause is that Gatorskins have some sort of sidewall protection that doesn't really work (as evidenced by me having a sidewall failure on Gatorskins), but interferes with the ride quality. The Grand Prix 5000 was folding because that's the only available for sale, and the Gatorskins were wire bead as that's the only available that was for sale back when I bought them.
I now want to replace the front as well which isn't so urgent, if I invest in a folding will the ride be more/less smooth or the same?
I suspect it does not make any difference, although my Grand Prix 5000 folding has better ride quality than Gatorskin wire bead, but that's probably due to the presence or absence of sidewall "protection" (that doesn't really work). Also I have had less punctures through the tread on GP 5000, but I suspect it's due to me being more wary of situations that cause punctures nowadays rather than the tires magically preventing punctures through some sort of "protection".
If you want good ride quality, ditch the Gatorskins and go for GP 5000, preferably as wide as possible (i.e. 32mm). Gatorskins not only have less than optimal ride quality, but they also have less than optimal rolling resistance, so you lose a lot of time riding slower than necessary.
Your 25mm does not make any sense to use, unless you have a ridiculous "road" bike that doesn't allow any wider tires than 25mm. Wider tires offer smoother ride, and also have less rolling resistance. Furthermore, you get less pinch flats on wide tires.