I disagree totally, I've had retro before and they are junk, their customer service is terrible and they don't stand behind their warranty. My buddy Daryl on here will tell you the same thing. I ended up throwing mine in the trash and wasting $190!!
Go with DDM tuning, ran theirs for years with no problems!
the retro 55w digital kit in my truck is awesome, no complaints, even with below 0 degree weather here in Wisconsin. I buy a lot of kits from them for my customers and only have had one issue with a bad ballast. They took care of it no problems at all. They are stand up guys in my book. I usually have them at my front door within two days.