Well you must be pretty slow on the track then!
What size wheels do you have on your race cars? Remind me - why is it race cars have small wheels again?
Why don't street cars have 25" wheels (or bigger) if that helps with all the things you mention?
Yeah, pretty slow. Tend to be top 5 fastest in local events and depending on what car I was in would set FTD. Keep in mind my region when I was active usually had several past national champions. Won several divisionals in my class as well as 2nd overall for the season. Normally finish mid pack at the Nationals. You know, the place where people trailer their street cars to the track to race. Where the top guy has a $25,000 car with $20,000 of parts. I have not been active for a few years as other things in life became more important.
What size wheels on my race cars? The lightest ones that fit the size regulations for the class (that I can afford). In most cases it would be a factory wheel as factory alloy wheels are generally very good and unless you want to spend $250 - $500 per wheel you will not see much if any improvement. Most people buy aftermarket wheels for the street and put "race tires" on the factory wheels. Although now the street classes run street tires so most buy a dedicated set of whatever tire is best that year for racing. Have you ever read an actual SCCA rulebook? I imagine not or you would realize exactly how ignorant your question is.
Do you just play Forza and read car mags or have do you have any actual experience with wheel tire setup / suspension setup etc. You spout terms like somebody with 0 practical experience but a lot of internet experience. Racing is not the Fast and Furious with Race Wars made up Hollywood BS.
Unsprung weight. LMFAO. You act like that becomes the sole variable in how a cars performance changes. You make a statement of that is just wrong with your only comeback is look up unsprung weight. OMFG, LMFAO.
OP was asking about changing tires and using the factory wheels. In how he drives the car unsprung weight will have 0 impact in his decision. What will having an impact is going from a 50 to a 60 series tire. Keeping the width the same at 215 you will have a decent increase in sidewall height. The increase in sidewall height will probably come with an increase of weight. It probably will have improved ride feel as there is more air cushion in the tire. I don't entirely know how it will change a timed 0-60 run (but I doubt he cares) but I doubt it will make it faster. The Bolt is traction limited in its performance. I have tested and know for a fact that a grippier tire on the Bolt will definitely improve the acceleration. The 60 series tire will definitely change the steering feedback and responsiveness of the car and make it worse (IMO, others may like the vague feeling). The factory tires are bad enough for steering response and traction. Also, just about any tire you buy will negatively impact range. This has everything to do with the tire compound used. The one thing that the factory tires are good for is delivering the maximum mile / kWh possible.