As for the price, its alright, nothing to brag about!
I dont know how many sets of HID's I have ordered from DDMTuning for my vehicles and numerous others and never had any problems that are the HID's fault.
http://www.ddmtuning.com/Products/Apexcone-Raptor-HID-Kit
You can get the simular kit at ddm for $30.
Tho you will have to add the brackets to it for $4
You also have the option for 55watt ballasts for even bright lighting for $10
and a relay wiring harness $15(not always needed but I install them on every set and brand I install just to eliminate the "what if" possibility).
So your looking at around $59, plus $13ish shipping = $72.
But you are gaining the relay harness which is not included in the linked set, nor like I said not always needed but strongly suggest!
Your also getting a LIFETIME WARRANTY!!! Which the place you linked seems to have none (at least that I noticed)...
You also have a wide selection of bulb color and bulb type.
The only downfalls of ddmtuning is shipping may take up to 2 weeks sometimes since some kits are dropped shipped from china but lets get real here, thats where all are made, hell I even stopped using Futurevision due to being idenical kits, at a heavier markup. ddm also dont give you a fancy box that will end up in your trash either. Sometimes the box may look a little beatup when the package arrives, but after ordering multiple times (over 25 kits) I had never had a single bad bulb, ballast, or anything missing in my orders.
As for you PS, no HIDs should not dim. they only require more power then normal halogens during the time the ballasts turn on for the first 4-7seconds (some vehicles stock wiring cant handle the exceeded amperage which is why I always use relay harness's) but once the ballasts are warmed up after the 7or so seconds, they draw less power.
The lights will not dim, since most brands I have used are in a voltage range of 9volts - 16volts, as long as voltage is in that range they will work as they should, any less then 9volts may not ignite the ballasts, any more may kill the ballasts. But again DDM = LIFETIME warranty.