My jetta has only lowering springs, and whenever it hits a bump, it feels like my suspension is banging because I guess it's hitting the bump stops... It's hella rough, it's worse when you have lower profile tires too. I got 50 series Falken tires. Do you have upgraded rims and tires also? I test drove a 05 Civic Si that had 18" wheels and probably like 30-40 series tires on it, and the thing was so bouncy and loud (road noise).... It ended up having terrible flood damage in another state, and they moved to Cali, and registered it as a clean title. Gota watch out for scammers....
I know I'm comparing apples to oranges, but just saying, they could be other factors to look into...
1990 Civic time-attack project
1990 Toyota Hilux - daily