
Next week my car's bonnet is gonna have a dent pushed out and then resprayed following damage from a falling roof tile. I'm considering replacing my current custom insulation shield with proper under bonnet insulation. I'll insulate each section separately rather than across the whole width like it is currently. Here's an example of what I mean:

Can anyone recommend me a certain brand / type / supplier of under bonnet insulation? Anything I should keep in mind? I would like it silver and as shiny as possible, almost mirror like.
Another option I've been considering is making up some myself. I've been pondering cutting up sections of corrugated plastic and covering it in kitchen foil using spray adhesive. I acknowledge it's sound deadening properties and maybe it's heat insulation won't be affective as the proper stuff but maybe it won't be worse the OEM part?