I live and love Aikido but there's little doubt, it doesn't mirror our most primal of fighting styles ie. striking for offense and having hands up guarding the head for defense. And I think these natural tendencies during unfamiliar non-Aikido bouts is the hardest thing to drill out of ourselves if we've come to Aikido with some understanding of other strike-based arts. Problem for me is when I practice Aikido, I like to try to maintain something of the integrity of the movements despite my training in other arts and that natural prediliction for their use when sparring non-aikidoka. Sure I know step-through side kicks and whatnot - most of us do - but personally, when I try to lead into a shomen-uchi with a one-knuckle fist [hehe!] I generally end up with neither one thing nor the other, my attack ultimately concluding in a weaker diluted state than what it might have been on sticking to the original. I think crosss-training and taking multiple arts can only be a good thing but in terms of modifying specific techniques, I feel that's where it has a tendency to go belly-up. But that's just in my personal experience. For what it's worth, I found that the one element of cross-training that brought me most gains [with specific reference to boxing-type opponents] was speedwork - training to stay up on the balls of the feet so as to maximise forward and retreat movements; practising the side-to-side movements as well as the circular; and my favorite, the repeated stance switches - I enjoy doing this anyway but it adds an extra dimension to your overall defensive proposition when sparring a boxer. And as I mentioned in a previous post, the very nature of the boxer's in and out style, if picked up upon, can I've found, be utilized with some natural atemi to break his or her balance. Let me know what works for you - I'm always interested in taking on board useable supplementary training or knowledge! Oh, and agree with Hand Sword - boxing ain't for the aikidoka! But we have other ways and means! Hehe!! Respects!