Are you joking?, improv is a metal thing?, dude, jazz in the most part is based on improvising, most metal players cant improvise that well, especialy compared to the jazz greats, theres little compromise at all in jazz guitar. You want to hear some great jazz players then you can start with Django Reinhardt and Joe Pass, and believe me, they can play lead just as well as they play rhythm, in fact, they often do both at the same time. Also check out John Mclaughlin of The Mahavishnu Orchestra, hes like the jazz equalvent of shreding, his edgy style would definitely appeal to you, check him out.