I used it in a heavy buggy, and it was plenty powerful. In a lightweight car such as an 8ight, it will be brilliant! It's as powerful as a 60mm Medusa, even though it's shorter, because it's actually wider than the Medusas.
As for covering the holes, I've seen different techniques, but the most popular seems to be to get a black bottle cap or round lid and use duct tape to hold it over the end.
__________________
|