I'm sorry, but this is a car which isn't worth upgrading to a premium.
(And this comes from a person which has loved Alfa Romeo's since my early childhood.)
We already have a premium 147, which is the facelifted and gorgeous Ti 2.0 TS. The 147 I would love to see as a premium instead, is the 147 GTA.
Why? Well, because of the magnificent Arese/Busso V6, the insane powertrain, the even more insane sound (Well, atleast in real life.) and also because the 147 GTA is most likely the best handling FF car in GT6.
If this was a 1.9 JTD, or a 1.6 TS, I would agree 100%. But since we already have a premium 147 with the exact same engine, better suspension, better exterior etc. I really struggle to see the point of having this 147 uprgaded.
Sorry if I sound like an asshole, but I wanted to say my oppinion. I usually agree with most of your suggestions, but this one is so far, is one of the few exceptions. Hope you don't hate me for this...