Well say for example you see an exhaust you like - either a universal fit one that you'd normally fit with a reducer pipe, or one of a different model of car. It's not normally that hard to cut/weld yourself a new exhaust. If you get hold of a universal backbox, all you really have to do is cut the standard backbox off on the collector pipe (so you still retain the flanged pipe, presuming that's how they are on K10s). Then just weld the reducer pipe onto the collector pipe, and then weld the backbox onto the reducer pipe (making sure it's welded on at the right angle). If needs be, you can also cut off the exhaust hangers and weld them on to the new backbox. Same with using a backbox off another car, just cut if off at the collector pipe again, but leave enough piping so you can weld a reducer pipe on to make it fit. That's what's been done to mine, and it works perfectly, as I couldn't find an exhaust to fit that I actually liked, styling-wise.