Hey Jamee ask the bodyshop if they are gonna mix in fibreglass with the silecone when they smooth it in that's what we used to smooth my other Astra and honestly mate it does take some pounding and by the way you "will" probably need to take care over speedbumps etc my Astra is lowered about 60mm on KW coilovers though! but you do start to pick up a sixth sense about potholes... lol the worst speed bumps are those ones that are like a half circle I don't know how many times I've turned round and looked for another way to go as I was that scared of scraping my paintwork that's why I went and got the coupe the Mrs was expecting and I wasn't gonna have a baby in the car while I'm swerving out onto the other side of the road to avoid a pothole...(so I just use her for shows now) I just noticed their that you haven't lowered it yet mate honestly if you do lower it which I know you'll be dying to do for the look either get coilovers a bit pricey but you can slam it if you're going to a show and raise it again for daily driving just make sure you get them set up by a pro!!! or go 30mm max on springs and dampers if that's your plan...
Hope this helps mate...