So basically no real difference
Errrrr… CHECK with your insurance company first… Seriously!
I say this because I know that many people have been caught out here as fitting different sized tyres (even just a profile lower) is classed as a modification, and insurance companies have refused to pay out as a result…
Sorry to be the bringer of bad news, but I figured you’d rather find out now rather than when your insurance company doesn’t pay out! Of course this may not apply to all insurance companies, but I’d find out first…
In the real world though, insurance company aside, as someone who’s done this (had a Peugeot 306GTi-6 years ago with 195/55/15 and fitted 195/50/15’s to it), I wouldn’t recommend it to be honest. Fine if you want a lower ride height for track use, but it throws the speedo out by a good few percent, your fuel consumption goes up (cos the car is now geared lower), and the ride will be slightly less compliant. It’s not massive changes agreed, but remember that your car will now sit lower to the ground by 10mm or so, but that the spring rates haven’t changed so it will bottom out on speed bumps and potholes much more easily now.
A far better bet is to change where you get the tyres from, and find somewhere that supplies good quality tyres at better prices…
http://www.blackcircles.com/
https://www.camskill.co.uk
Hope I’ve helped