Congratulations! I have a very similar 2009 vert - taupe interior and without the cold weather/bluetooth packages. I still love it. I drove the 135 at PCD and liked it but I think the 128i has plenty of power. You just need it in the right gear when you want to move out quickly. Enjoy!
Our weather is warmer here but I comonly drive topless in the upper 30s and low 40s when it is sunny. I get some top down drives every month. We've started the time period where I almost need the top up for the AC at times.
A windscreen will make higher speed driving more enjoyable especially for those with longer hair. It's pricey but works well. I got mine from a BMW dealership selling on ebay.