Many of us have run same size tires & wheels front and rear for many years with no problems. Twinspopa is exactly right the additional cost of wider tires is offset by getting longer life and greater mileage out of each tire do to the ability to rotate. X5Kiwi, can't you just order tires from someone outside New Zealand and have them shipped to you? I order my tires through tirerack.com they have a very good selection. On my X I have run the Michelin 4x4 Diamaris, Continental 4x4 Sportcontact, Dunlop SP Sportmaxx & Pirelli PZero Roso. I found the Dunlop's and the Pirelli's to be superior, with my favorite being the Pirrelli PZero Rosso.
I have included a link to the tirerack.com page with additional info on the tires I have run.
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