If you prefer a deeper profile you'll need to change your wheels as well, down to 16s in order to achieve the same rolling circumference. Then you can probably fit Michelin Pilot Primacy HP, which have lower rolling resistance. DEFRA and TUV tests have shown them to last an average 20% longer than other makes and types of tyre. If the tyres are worn unevenly, you need a '4 way laser alignment' at a
branch of www.alignmycar.co.uk