I've run them for 12K miles on the 911, and they're very good. They're not quite as grippy or communicative in the wet or dry as the Michelins, but they're a pretty close second. They do wear better though, I'll give them that.
18 months?! Blimey, the wheels could be anywhere!
Without getting too bogged down in detail, if you had the front wheels toeing out (i.e. pointing outwards from the car) then when you turn into a corner, the wheel is already pointing in that direction so it will turn in much quicker. You'll lose straight line stability at speed (meaning it can be a bit twitchy at motorway speeds), but then any alignment is always a compromise of something. If you had toe in, you'd get the opposite. Apologies if I'm teaching you to suck eggs here.
With camber, if you stand the tyre straight upright then when you turn into a corner you will lose a significant amount of contact patch, and so that tyre will suffer from lack of grip. If you add camber then you'll get the opposite, so more grip into a corner but increased inner tyre wear over long distances.
Combining the two into a combination that works for you is a true art form, and I'm not sure where you're based but Dixon at DMS in Erith did wonders for me on my car. Abbey should be able to do the same, or a multitude of places around the country. I have my cars set up with a little toe out and maximum camber at the front, and then the rears almost upright on the 911 but cambered over a touch more on the MX-5, which is probably more like the setup you'd want on the Zed.