If you're looking to improve handling, then by all means, go for it. If you're also looking for cheap tires, it's probably not worth it. Generally speaking, low rolling resistance tires also have significantly longer life. After searching and posting on this forum, I just bought General Altimax RT43s for about $105 - $107 each at Walmart. Low rolling resistance, 65K mi life, but better ride/handling (so far, so good, but we'll see).
You may know this, but since you can't rotate the tires, the warranty will be cut in half. And you'll see MUCH lower life. I just changed the tires at 45k mi, but to be honest, really needed changing at 37K mi. And this is the third set of front tires. Yes, the third set of LRR tires, needed at 37k mi. The rear tires were original and still looked new, with no measurable treadwear, but did have some dry rot, so they went too.
So, if you buy cheap, softer tires, for, say $60 a tire, they may have 35k mi warranty, cut in half, and expect even less. I'd take a guess that you'll change them twice as often, so, that would be 2 x $60 = $120 per tire instead of 1 x $105, plus an extra $25 each tire for twice as many installs.
I live in the greater New York area, where electricity is pretty high. I would estimate that a 20% reduction in range would cost between $200 and $240 over 30K mi, so add another $50 - $60 a tire, well, $25 - $30 per tire if you change them twice as often.
You can also find cheap tires with 60 - 80k mi warranties, but that wouldn't achieve your goal of a softer, better handling tire.
Personally, I found it very difficult to find tires for the Spark. While I didn't have to, I wanted to put the same brand and model tire on all four wheels. It was hard to find anything available that would fit both sizes all around. I ruled out any no-name brands I wasn't familiar with. Whatever you decide, I hope you let us all know how it works out.