I got the Ultimate and was slightly miffed about the quality of the release but you should have no problems at 30fps. I tried that and while it feels like it's in slow motion (too used to 30fps), it doesn't drop or stutter. Thankfully, the 1070/4790k can power through the issues and more or less hold 60fps outside certain parts of Surfers.
I'd grab a couple of cheaper Live cards and redeem them on Windows Store. That way you'll be able to save a bit on the Ultimate, if you're absolutely set on it. Frankly, you'd be hard-pressed to find a better game for car enthusiasts.