Ive got a 2000 Kat 750..Ive beaten several 600's, CBR's and a GSXR600...and not all of them were stock either. I can get my front wheel off the ground, but it does take alittle work...(although I dont make a habit of it)... Kats, being the original GSXR, arent geared quite the same, nor do we have the same torque carried by the GSXR. Plus since they are considered, technically a sport-tourer, they tend to be alittle heavier.
The Kat is a good all around bike that does everything well and will last a lifetime if she's treated right. She'll take the twisties with confidence, is very forgiving to the rider, and gets me to 150 mph with no problem, which is plenty OK with me
I've found when racing, not to run as high RPM's in first gear as you may want too, maybe alittle higher than mid-range or so, then get on it in 2nd, etc... as most of our power comes in 2nd & 3rd gear. Kats have good midrange, and decent top end power, but not the best off the start, so light to light..it can be difficult to win..but over nice little run, you can hold your own, the majority of the time.
Plus you have to take into consideration, what kinda mods those 600's had that u were racing.. jet kits, exhaust, etc..hell, even the oil can make a nice difference in the acceleration of the bike.