I can confirm the Garmin model has live traffic services, but be aware that it uses your mobile phone for the data via bluetooth tethering & according to the instructions can only get the info from an iPhone or Android with reasonably current operating systems. My wife has an iPhone 3GS on iOS 6 & it works with that. I tried it with my daughter's Windows phone, but as that can only tether over WiFi it did not work.You get 1 month free & then when we got ours for around £20 you can update for life. If you don't use the live services the Garmin unit can default back to the TMC service that the earlier Navigon units have.
For Seat, the changeover time for the units was June / July last year. The units (even if standard on the car) are dealer supplied, they don't come from the factory in the cars. When we were looking at an Up! White the dealer said the Maps & More would come from the parts dept, it was not already with the car.
However, I have just looked at the current online Up! brochure & price list & both show the Navigon unit with no word of live services whereas the Seat website calls the unit Seat Portable System Live.
Based on what I have seen in the VW brochure I can't even guess what unit your car will have, best check with the dealer.
Edited by: mii al