An easy experiment:
I got some tires, which are 5 grams heavier each, than my usual tires. The interesting about this is, that it highly illustrates the effect:
Drive some laps with one type of tires, then some laps with the others.
Of course, it'll influence on handling, but when it comes to acceleration and deceleration, it's very easy to feel the difference. Especially since wheels can be changed so fast, that it's easy to feel the change.
Try measure the weight of your own tires, maybe you can do some testing here yourself.
What surprised me, was the less braking with the heavier tires, I often entered the corners too fast.... Not surprising, when re-thinking about it, but it wasn't what first came to mind, when I was planning the test.
JesseT got some good points about motor placement, that is, belt versus shaft.