I fitted Eibach Sportlines to my 172 back in February and had new tyres shortly after (my old ones were worn out before I fitted the springs).
Since then, I've only just (as in today!) needed to buy new tyres for the front. That's 7 months on a set of Toyo T1-R's, which I don't consider bad at all.
The rear tyres don't look like they've worn at all and I've easily covered 8 or 9 thousand miles on them since fitting the springs.
Hope this helps.