I don't know much else but BSW. I'm not going to say that's the only option, but I am curious as to why you want to avoid them. They are a perfect fit and they are definitely an upgrade to the shitty paper HK speakers. My HK midrange/tweeters were blown in my car. The BSWs are cheaper than OEM replacements and are made of superior materials. I imagine the door speakers are the same. All your other options will include making some sort of adapter to fit the speaker into the door and splicing some wires. Not that hard if you are handy. You can probably get great setup with some 6.5 inchers from Crutchfield. You just gotta make sure they are shallow enough to fit. Our speakers mount to the door trim instead of the door frame, so they aren't as deep as most speakers. I wouldn't be surprised if Crutchfield had an adapter too.
As for what Wasp suggests, I can't agree more on the rear deck. I took mine out and put in an Infinity Basslink with a custom mount over the battery tray. I actually have bass now. The stock 6x9 woofers total 64W in power. It's kind of pathetic. I couldn't even hear them. The 200W Basslink is enough to fill out the lower range.