That's a bargain. The TechArt's are like x10 the price including import + tax costs.These are the ones I got. Purchased from my local mercedes dealer for $130. Each one has 2 wires. Found on 911.uk the wires to tap into.
They are metal at least and not cheap plastic!
Look at Raid since they mfg for Techart and FVD. Otherwise, you can go OEM route with PDK wheel, module, and dealer programming.techart items look nice but the cost is pretty high...
was thinking of getting a new steering wheel with paddles instead as I don't have the multifunction buttons on mine and sport design looks nice too.