Can't help ya with the cost difference as all I see is white light
You say you want to just have the lights run off the headlamp switch. Well you're in luck. My idea will cost you a bunch of wire and 4 relays. Plus a fuse assembly or 3.
LMK if you want to do it and I'll draw out a diagram for ya. It's really quite easy for anyone who's ever done any kind of wiring. Ya just need to know how to crimp connectors. And its a good idea to put all the wire in split loom to protect it from chafing.
To recap -
if your car is wired the way I'm thinking;
My plan will give you LEDs when your Headlights are off (DRL mode and with no dim Headlights), Headlights on without LEDs, and lights will be controlled by either the ignition (better idea) or the headlight switch (probably not up to snuff for proper DRLs, and you'd have to put on the marker lights to run the LEDs).
The only concern I have at this point is what will happen when you put on your High beams. It's possible the LEDs would come on too with my plan.
When are you in POCO again ? I could look at you car on the way home from work around 4PM.