[lucideer]

There's huge variation in taste of both canned tomatoes & passata between different brands, and I've made much better pasta sauce with fresh tomatoes than a can. When they've been good, in-season local tomatoes. I've also made worse pasta sauce with fresh tomatoes in winter.

I'm fairly sure the quality of the ingredients will have a much bigger impact than temp.

That said, cooking on a low heat for as long as possible does give you the best results.