Well Toriko never used a GT Robo but Regal mammoth Arc Starjun already exceeded the power level that the GT Robo could bring out. I don't think that a stronger user would make the GT Robo stronger once that limit is reached if that's what you had in mind. My point being that Starjun's GT Robo is probably as strong as you can get and that pretty much regresses this back to Regal Mammoth Arc level Toriko.
i kinda disagree on this one.
the user can project his aura through the suit so watch out for the ultimate impression.
stats wise id have to agree. the GT robo cannot keep up with toriko at all.