Not a whole lot actually. Some may find it hard to believe, but I've done tests. I made recordings of a guitar that I modified, before and after, keeping the electronics and the amp settings the same. I could here a little difference on playback, but nothing objectional. In fact, if I had to pick, I'd say I liked the "after" recording better.
Keep in mind that the key areas, like where the bridge and neck join the body, have not been touched. I think the species of wood affects the tone a lot more than the total mass.
A friend of mine built a guitar onto an oak log that weighed about 20 pounds. He did it as a joke, but it actually sounded like...and electric guitar! I guess my point is that a 4.1 pound guitar body generally doesn't sound that much different than a 4.5 pound body.
I do find, in my experience, lighter guitars sound more alive and heavy ones sound a little more flat. It makes sense as the wood can resonate more freely. My favorite sounding guitar is a Warmoth chambered mahogany Strat. I didn't carve it up, but it's missing about the same amount of mass as this Tele.
Hope that helps!
