I don't know if this is accurate everywhere or just locally, but I have been told that you cannot change out the ballast and the ends of existing fixtures and keep up to code. The fixture itself is part of the UL listing and by removing the parts that made it UL listing and putting new parts in and not having it UL inspected, it means if you upgrade your existing fixtures, you're not UL compliant.
This probably isn't a big deal for the home owner, but it's about to become a very big issue. Right now a lot of commercial buildings are doing the conversions, but the inspectors are starting to go after it now. So just know that trouble is on the horizon in this change over thing and you can bet somewhere, somehow, the cheap solution is going to get shut down.
Lasers : Trotec Speedy 300 75W, Trotec Speedy 300 80W, Galvo Fiber Laser 20W
Printers : Mimaki UJF-6042 UV Flatbed Printer , HP Designjet L26500 61" Wide Format Latex Printer, Summa S140-T 48" Vinyl Plotter
Router : ShopBot 48" x 96" CNC Router Rotary Engravers : (2) Xenetech XOT 16 x 25 Rotary Engravers
Real name Steve but that name was taken on the forum. Used Middle name. Call me Steve or Scott, doesn't matter.