Reelimpatient

Just got this 96 gtx and had it out on the water for an hour. When I got it, it was hydrolocked. Got it cleaned out and seems to run fair. On the lake, it has a bog area at 2000-3000 rpms and then takes off and runs great to 5500.
But the 5500rpms is wide open and everyone I talk to says it should turn over 6000 at least. I took the carbs off and plan to soak them in some carb cleaner or seafoam. Then I read a thread about gray fuel hoses, and wonder if I should change them.

The questions are: Anything I should be careful of when cleaning the carbs?
Also, at this point, should I also do the fuel line change out or do one thing at a time? The 2000-3000 rpm thing bothers me and would like someone to give me an idea about what that could be, that's why I'm starting with the carbs. It has new plugs in it already.
Any help or ideas from experiance would be most appreciated !

Thanks !