I have the Euro headlight & handlebar switch and a DDM Tuning
55w 5000k H7 HID in the low beam- incredible! I have a 55w 5000K H3 HID for the high beam and it really makes a difference. The Euro switch allows you to start the bike w/o interrupting the start-up of the HIDs, once the bike is running I turn them on. Considering they are now $22.50 each (cheaper if you buy dual kits) they cost less than the halogen bulb replacements on my pickup truck...
You can mount your ballasts anywhere, the length of wire used isn't going to effect anything. I mounted mine to the sides of the headlight bracket, no space issues.
I added these Hella FF75's under the nose for 'ditch" lights- 55w each of H3 halogen fun- I can see all the critters and during the day nobody is gonna pull out in front of me!
I have the high fender & tall (full) SW-Motech crashbars installed- no clearance issues.
I modded the Euro switch wiring so the parking & headlights come out at the "park" switch position, then the Hellas come on when I push the switch to the "headlight" position, thus alleviating the need for extra switches, and I don't have totake my hands off the bars to turn them off for oncoming traffic at night. Of course they run off a relay from the battery- don't mess with the ACC1 or ACC2 leads as the wires' gauge is too small for lights, heated clothing/etc