I just got my Swing and it didn't have a topbox so I started looking around. At first I saw the GIVI's were popular so I checked them out. I wanted one that fit two full face helmets so that was going to come in at around $250 for the case (E460 46L) and another $50 for a backrest. (I used to own a Vespa and I paid $530 for a top box that only held one helmet!) Then I looked on e-bay and found a company called "Bestem". I ordered the Tbox 929 which comes with mounting plate (top box is removable), backrest, and brake light for $79.00!!! I live in Canada and it took 8 days to arrive (they estimated between the 6th and 12th of Oct, it arrived on the 5th) and cost $43.00 to ship so I'm all in for only around $123.00!! This model only comes in black which at first I was skeptical about but it looks great and I don't have to worry so much about scratches as there is no paint on it. I scratched the one on my Vespa and it looked terrible because it exposed the black plastic underneath.
Anyway, it was easy to mount. I had to drill four 5/16" holes for bolts (I used some much shorter ones than supplied) and another small hole for the wire (haven't got that hooked up yet, still have to figure out where to tap in....). There were four rubber spacers supplied, two of which I was able to insert in existing bolt holes in the plate and the other two I had to cut off the stems and just place them beside the two bolts closest to the back. Just have to be careful where you drill the holes because of the ribbing under the carrier and where the plastic cover attaches underneath. The front part of the mount sits nicely on the curve of the carrier. All in all I am quite pleased. The box is easily as good quality as my previous $530. model. The only small bitch I have is that the latch is what I would call a bit 'fiddley" but once you get used to it, it is fine. When you unlock it, you can easily pull the big red release catch and take the box off. The wiring has two connectors which also come apart easily so away you go!
So I just thought I would share this as I do find some of these top boxes ridiculously over priced.
Next up, new windshield and heated grips!
deep

Deep said : "still have to figure out where to tap in."

You might consider looking at Dennis' perfect connector...

http://www.silverwing600.com/t2847-the-perfect-connector

It will save you any wire cutting. A lot of us here are using it for our scoot.

I have a Bestem on my Reflex and it's not bad for the money, but I have some issues with it.

I bought the GIVI mount (I think it's called Monokey) for my Silver Wing because of how well it integrates into the rear deck of the bike. The Bestem version almost seems like it would fit in the GIVI footprint and the front part actually does slide in correctly (I believe because it was a GIVI clone), however the GIVI latch and the Bestem latch are on opposite sides of the locking nub thingy so it doesn't work.

HOWEVER- If you have the GIVI mount (again I think its the monokey) and you buy the large JCWhitney trunk (also a GIVI clone) it will fit BUT due to minor design changes to the latch over time you have to do some minor modification to the latch on the topcase to get it to line up to the nub properly. That's what i use on my bike- it looks super-clean and you don't have to use that crappy-looking mounting plate bestem provides.


Jesse in Atlanta

Jesse, I've just noticed it states on the Bestem site that their boxes won't fit on the Givi plate....as you discovered:

http://www.bestemusa.com/product_info.php?products_id=683

IIRC Shad boxes fit on the Monolock plates.

As for prices: indeed Givi Monokey boxes are expensive but they are robust (mostly double-skinned) and last for years.
There is no distortion or flexing and they are very secure.
I've had mine six years and it's like new.

Hm, my Swing came with a Bestem box and a Givi mounting plate, and it works perfectly. Maybe it's just because the box is an older model.