While I'm no expert on this, I'd guess that more than "speculative" they might be player dependent. I've never done coke, but a friend was the manager of a band we used to go see a lot. I won't say their name since there are some guys from around Cinci here, and they were pretty popular. He told me of times the band was paid in coke for gigs. Anyway, the guitarist was GREAT. He was shredding most big name guys in the late 70s and they came really close a couple times to breaking on the national scene. I remember being close one time and "thinking" that he was incredibly intense and focused... LOL We saw them multiple times and he was in the zone every time... A few years later the band had broken up because they just never got that big break and other members moved on to "jobs" and families. He was playing in a top 40 band. I couldn't believe it. Like THE rock wildman guitar player from Cinci was playing pop music now???? My friend said that he got off the coke after that band broke up. I went to see his band a couple times just to see him. He was a totally different player. He could still rip when he wanted too, but was much more laid back and the intense look was replace by a smile.
When we talked to him after the show, he told me that the shredding he did "back in the day" was "chemically enhanced." He said "I'm fast, but not THAT fast."
As for myself, I can only speak for weed. I figure basketball at the level I played at is way more difficult than playing guitar. No "reaction" to someone or a whole other team playing defense, on the guitar. Drinking even a few beers and trying to play basketball was a disaster, while I could still play guitar pretty well until the buzz kicked in more then I got "looser." So, This is not in my mind at all. I played basketball and guitar better with a weed buzz, than without. I have friends who will vouch for both. Weed was a mind enhancer for me. Just made me more "into" whatever I was doing. It put me "in the zone" for anything I was doing. But I know it can affect people differently. I'd be life of the party funny guy when buzzed while some of my friends were just mellowed out buy it.