I've recently changed from 17" to 18" tyres. I was previously running on Michelin PS2 at 35psi (F) and 32psi (R) for everyday use on the standard 17" GTA teledials with great results. I am now running on Bridgestone Adrenalines (which, IMO, are so far no match for the PS2 in dry or wet) on 18" OZ Ultraleggeras. At higher pressure, 34psi (F), the steering feels light and there is a vibration at 100kmh onwards. At lower pressure, 26psi (F), the tyres howl quite loudly when driven enthusiastically, but no higher speed vibration. I had all wheels balanced and aligned. Suspension is AD adjustable coilovers. What is the recommended sweetspot for tyre pressures on 18"? Thanks!