I usually have a multi-car discount that would take, say my $190 down to 160-170 or so for both cars, or maybe just add a bit to the total, it's usually a huge benefit. I just bought a 2018 Miata RF last week ($22k w/30k miles since its on topic) and it added $150 to my insurance.
I can't believe it. Yes I quoted before hand and still did it, and shopped with an insurance aggregator (thezebra). Switching from Geico to Progressive saved me a little bit but not much.
Also, anyone who loves sports cars and hasn't driven a 4th gen (I haven't driven earlier) miata.. do it. It's so fun and it's not 500hp like my last sports car that was so fast I was way over the speed limit in 2nd-3rd. I'm redlining the RF constantly and still getting 28mpg. I get to hit 1-4 to hit 60 I think. It's a really fun active drive and I can't get any body roll at all (mine has Tein coilovers).
My friend works for an insurance company and it's all the car thefts going on he said.