I read a pretty cool article on the different qualities of HID bulbs. I would imagine that this rule applies to most aftermarket ballasts as well. That being said, there are conversion kits that adapt that ballast to your D2R/D2S HID lamp should the ballast ever take a dirt nap. ALWAYS have spares of the cheap stuff. It could last a year or it could last a day, but they're cheap enough to be prepared!
I've installed DDM kits on a Ford Taurus (mine), Ford F150 (friend), Saturn Astra (friend), Mazda Protege (wife), Nissan Frontier Nismo (friend), Ford Fusion (brother), Ford Fusion (friend), Chevy Equinox (wife,current), Volvo 850 (mine,current).
That totals 20 ballasts because the F150 I did the foglights as well. Only ballasts I had fail were the foglights because I brain lapsed and didn't waterproof the connections at all. DDM still tested them (failed of course) and replaced them.
DDMs service sucks if you don't have patience, wait times for shipping are upwards of 5 weeks, but I have to say I think I can claim I have more experience than most with them and I haven't had issues with quality or their lifetime warranty. They are certainly not as bright as other HID kits on the market but are still worlds beyond halogen bulb technology. Personally, I don't need to have the absolute brightest lights on the road.
All that said, not sure if compatible on the R, I don't think anyone has tried. They may work in place of the OEM ballast but idk if they would throw low beam out messages on the dash.
Addition: Forgot I have them on my SR in the foglight position as well. That makes 22 ballasts.
I have 55W DDMs for my fogs but I waterproofed everything from the ballasts to the wires with liquid electrical tape. I've had no problems but if they do fail I would go with a Kensun ballast from Amazon. I have 35W Kensuns for my DRLs and Ive had no problems, with them being shut on and off a few times during start up. Plus Kensun is right here in the US so if you have a problem, you'll get a new one pretty quick