I'm skeptical of the silicone route, but about 6 screws with some decent size washers would get the job done.
In my case, my firewall and the whole underneath of the car is covered in a product similar to Line-X, and this product would spruce up my firewall nicely, even if there we some screws visible. Most of the screws could likely be placed in spots where they are hard to see anyway.
Given it is aluminum, it would cut down on heat transferred into the interior through the firewall too, a reason I've been thinking of doing something like this, even more so than the aesthetic reasons.
It looks to me like it is designed to be a simple install and might not have a completely finished look on the edges. I would like to see one in person or at least some more detailed photos before I purchased one.
__________________ Steve Hayes
"Dust Off"
68 Camaro
Speed has never killed anyone. Suddenly becoming stationary, that's what gets you! "Jeremy Clarkson"
16 gauge aluminum sheeting is really thin and soft. A lot thinner than 16 gauge steel. 0.0508 in aluminum compared to 0.0598 for steel. Any little bump or slip of a screwdriver/wrench would either gouge, dent or scratch it pretty easily. I've seen the undercover innovation ones and I wouldn't use it for anything other than a quick dress up for a really nasty firewall for a show or something. I can't see them lasting for daily use.
Silicone would probably hold it fine as it's very light.
You can't weld ALUMINUM to STEEL.... so those suggestions are just a matter of not reading the information given.
Like most of this stuff.... it all "depends". Depends on your goal - budget - skill - tools - time - and the end result of what YOU are trying to do. A build with a high budget wouldn't think about using something like this.... but my brother in law had something similar made out of steel sheet - painted to match his body color - and had won many local show trophies. His was not only a heavier gauge - but was relatively well done.
During this latest "re-do" we discarded that piece and used the DSE version and normal welded plug and bondo method to smooth his firewall -- and it's no question that this method is more "professional" and nicer looking.... but the other method served him well for 6 or 7 years.... so it's just a personal choice.