I think high grade and low grade matters to a very small extent. Ultimately the tone and playability depends on the guitar, but low grade wood might compromise reliability. E.g. neck warps more easily, body more easily dented, etc.
I've always wanted to say this online here... Not necessarily to you, so don't take it personally...
You are talking COCK!:mrgreen:
There... I said it.
High graded ash and low graded ash can mean the whole difference in weight and tone. Swamp Ash and Northern Ash has a big difference due to the amount of pores in the wood due to the swamp waters. More air could lead to a lighter body, and more air in the wood, leading to a more resonant body. That wood, being already so moist and to water logged, takes a longer time to dry out and dessicate, which means more money in the process. Hence being "higher grade".
High graded Mahogany could mean the difference between Honduran light weight varieties vs the heavier other breeds of mahogany. Those who are lucky enough to have a custom build will know they pay thru their noses for Honduran Mahogany.
Brazillian Rosewood vs Indian Rosewood? Same thing. BRW is now very rare, and therefore more expensive. The small fact that is was previously used on the famous 1959 Les Pauls back then was also a contributor to the demand. It's NOT the same tone as the IRW found on today's Gibsons either.
Low grade wood simply means cheaper wood, but technically, quality or not depends a lot on the drying process and the cut at the factory. Warping and twisting has got to do more with care and maintenance, and not wood breed.
Basswood was ONCE viewed as "cheap" woods, and undesirable... This was back in the 80s. Now, there's a demand for basswood, and the prices are getting higher due to more demand. The generations of kids back then grew up on tones delivered by Joe Satriani, John Petrucci and the likes all knew that the woods used then were basswood. Hence the demand now since they all grew up on RGs. I personally prefer basswood for superstrats, having grown up on Ibbys.
So who's to say that basswood is inferior?
But again, why is there a KEY difference between a JS100 and a JS1000 in terms of weight?