My Bose HU is busted. I will buy an ROEM-NIS2 adaptor and keep the Bose amplifier and speakers.

My questions is if I go for a single din aftermarket HU, where can I buy cover/adaptor to cover the gap?

I would prefer online stores.

 

Scosche and Metra make the kits. I don't know of any sites off hand that sell them. Usually if you are going to buy an HU from an online source (like Crutchfield), they will send you a dash kit with it.

 

I just bought a Clarion HU for my 3rd gen Max. Bought from Cardomain.com, they included the dash kit ('pocket' to cover the hole in the dash), the harness and some wire connectors with the HU purchase. Put it in today. Two Thumbs Up.