He rates higher than people want to admit. He's been around forever. He probably would've beaten Abraham if that fight happened. I don't think he'd beat Taylor. Trinidad and Pavlik could go either way. Martinez at his best would beat him.
Hard to say. There have been a ton of good names who have inhabited 160 since 1990, but many of them haven't called it home for very long. For that reason, Sturm probably rates fairly high. Maybe top-15. He has had great staying power, and surely that counts for something, but his competition hasn't been all that good. Excellent jab in his heyday though. Oh, and to answer how well he would have done against contemporary greats, I think he would have fairly well. Taylor didn't mind keeping distance, so I can envision a jab battle with Taylor's natural gifts pulling him through a close one. I think he would have done well early against Pavlik with his jab and quickness, but Sturm never moved that much and Pavlik's work rate and power would have broken him down late. Martinez would have outboxed pretty clearly, in my opinion. Golovkin would have beaten him up and Hopkins would have beaten him clearly.