I have ran with all the years and can keep up just fine.
Las Vegas Ruff Ryders
Last night I was out on a '86 GSXR750. I bought this bike 3 years ago. And until yesterday, I NEVER rode it. Not one mile (long story.... for a different thread)
I was riding with a 2005 GSXR600. Off the line and even with the roll ons on the freeway. no comparison. That 600 flat out kicked my butt!
That is until we got in some twist. Now remember I had never ridden this bike, it is bone stock and OLD as the hills. my normal ride is a 2006 GSXR1000 so I was not even close to being used to the bike. But I left that 600 like it was bolted to the road. Why? Because keeping up isn’t always the bike but it has a lot to do with the rider. Sure, anyone can go fast in a straight line. That takes zero skill.
On to you statement/question. As stated I currently have a 2006 GSXR1000 as well as a 2002 GSXR1000 while I haven’t owned a 03/04 1000 I do have a to say that the difference from the 02 1000 to the 06 1000 is an OH MY GOD experience. They are both excellent machines that do certain things extremely well. But for the overall package the 06 is noticeably different / better.
So IMO the 03/04 is just not as good. It might have the power but the chassis is superior on the 05/06. I have ridden many a 03/04 and honestly think that even in comparing it to the 01/02 I prefer that later. My best way to explain the 05/06 1000 is that they took a 01/02 GSXR1000 and a 04/05 GSXR600 and had a baby!
Your '03 is a nice bike but it’s not the same as an 05/06. It is possible however that at your current skill level you cannot tell the difference between them. Maybe you just assume that they are all the same or close to it because there isn’t that in your face night and day change like from 86 to 05.