They also went on that the sleds didn't conform to ISO din because they couldn't be mounted with the side mounting brakets that modern cars use.

This was exactly the case with the install in my '96 Camry. I watched the guy as he showed me how it didn't fit right. He wanted to mount it without the sled, but I explained to him why that wouldn't work.

He ended up pulling out the handy dremmel. After about 30 minutes of that, the empeg fit nicely.