I'll steer clear of clen from now on. Opinions on ephedrine?
I do a bunch of cycling too, a few hundred miles a week. I'm not sure about what you got, but when I tried it last year my endurance shot through the roof. I could maintain unheard of speeds, for me, on the flats for way longer than I ever could before and at lower heart rates! Climbing didn't seem to improve, but didn't get worse.