Did you have it aligned when you lowered it? What were the specs then and now? I'm curious why he felt it was the shocks and not the alignment. Pics of the wear would be nice to just see what it looks like.

60,000km = 37,000 miles

Those are all-seasons right? I've only used summer performance tires and usually only get 10-12K miles on the rear set.

I would be throwing a party if I ever got 37K miles from ANY tires.