1. I get most of my stuff from Thomann, and although I have had a few issues the test of any retailer, online or otherwise, is how well they deal with the issues - in this regard I cannot fault them, although I think I have learned that their guitars are amazingly good at the price (I also got my Prophesy from them at a bargain price), but their own brand bass guitars leave a lot to be desired. I eventually sold my HBZ2005 after it developed an earth hum that I could not eliminate even after regrounding the bridge pieces and pickups - I didn't find the neck comfortable, too round, so this was the straw that broke the camel's back - it must have been a problem with the cheap as chips active circuit. I now have one of their Progressive Series basses, a 550. It was a nightmare to set up (but it's OK when done), and the finish on the edges of the neck is rough. It does, nevertheless, play quite well. The big problem is the electronics, again. The active circuit is always live, so I have to remove the battery every time after I have finished playing it. Again, this must be an internal leak somewhere: I've ordered a £3 mini switch to disconnect the battery as I really can't be bothered to send it back. I only wanted a 5 string for occasional use, so it'll do.
2. Vanson Guitars; eBay shop. I bought some pickups and a bridge from them - excellent service and good value.