If I was going to just getting an old bike running and hadn't ever run Commando's many miles I would avoid this two into one. Get a nice old beater set to run for now. Make your choice for a new set after some run time. There is a learning curve on these systems because of the ISO mounting system the order of tightening the bolts and the head clamps baffles many. I sure have seen a bunch of folks wanting to sell off their two into one systems after some use and I think that it always to do with the fact that it's a much harder system to mount and keep tight. Talk to a lot of real owners about systems they like.
RGM do 11/2" tuned length front pipes and straight through peashooters and these work brilliantly on both my 750 racer and my 850 2A roadster.2 into 1s never seem so lively or free revving to me. Any weight saving is negligable and careful mounting along with ISO adjustment is very important plus they look crap IMHO!