peping up a z650

right now i have the bike running right i'm looking into getting some tuning parts. nothing silly just a bit more grunt.
so 750 cams fit if you swap the chain pullys.
750 barrles fit, but its hard to find them in the uk
head i will port and 3 angle the seats
dyna ignition set up
have 2 compleat gpz550 motors any parts of them that i can use?
what about carbs, are my standard slides going to be big enough?
allready has a kerker system on it and have just got a stock airbox to go on it, crappy pods fitted at the moment and its a allweather bike.
what else?
cheers rob

Bigger carbs are the most bang for the buck. I fit a rack of vm26 (stock on some of the KZ900 and KZ1000 bikes, mine came from a Suzuki GS750), and that woke her up A LOT. Unless you have really soft carb holders you'll have to get a set of carb holders for the bigger carbs and stretch the mounting holes with a file or dremel for the carbs to bolt up, then jet them accordingly (mine are jetted with 17.5 pilots and 117.5 mains IIRC and I'm running K&N pods and lightly baffled 4-1).