Hmm, I've got a little 30 second MP3 demo of how it sounds, but being a bit of a techno-phobe dumb ass I don't know what to do with it so I can link to it, as it's just sitting in my girlf's laptop at the moment. Where do people usually put their soundclips?
Anyhoo, in answer to your question, in parallel there is a bit of noise. More than series, but still less than single coils. So it's kind of a half-way house. The sound is very difficult to tell from standard single coil (I'm comparing it to my Jap squire strat here). If anyone can tell me how to post sound clips it'll be easier!
I can't recommend any particular pickup cos I'm still new to humbuckers! Depends what style you want really. I've got a seymour duncan stagmag cos they're meant to sound more like single coils when split (so the blurb says). Compared to the original dragster pup, I'd say it's got a slightly richer mellower tone in series mode. I've never split any other pickups tho so nothing to compare that aspect with! The seymour D website is pretty useful
The wiring isn't complex but it is fiddly so if you're not confident with a soldering iron might be a difficult job!
Your covers rattle? That's weird, mine are wedged on good and tight, with a dollop of solder on the bottom.