Probably a subject that has been done to death, but I'd appreciate some up to date and reliable advice.
Up until very recently my Gpz1100b2 has been running an ally box section swingarm made from a 750 unitrak one adapted to accept twin shocks. The bike recently got a partial rebuild including a fair hike in power output. Either the extra power or just riding the bike after a few years lay off made it apparent that something wasn't right with the handing. Subsequent investigation revealed that the chain run was out of line by about 5 mm, so were the shock mounts. So much for my engineering skills in 200and whenever it was. Dumb ass...

I still have the original swingarm with good bearings in it so I refitted it and went for a spin. The result is that it generally steers better and is more accurate, unless I hit a bump leaving a corner under power, then it swings its pants around all over the place just like it used to.
I've concluded that it is worth having a stiffer swingarm as it does steer better in corners but my previous effort was too shoddy.
Any advice for a sensible upgrade? I want to run the original wheels and the easier the answer is to adapt and fit the better. Money is not no object, so dropping a grand or so for a lovely thing from Japan can't be done, much as I'd like to.
Anyone got a JMC or similar for sale at all please? There's a mechmatex off a Z1000A on ebay at the moment, but I don't think it'll go straight in will it??
Many thanks,
Olly