So it's your first bike... I understand your emotional attachment to it and not wanting to trade it in. If I were you I'd find a way to keep it... I bet there's not one person on this board that doesn't wish they still had their first motorcycle. Me? '64 Honda 305 Dream. I've been looking at them on Ebay lately.
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If you really want to hot-rod your 600, have you thought about putting a turbo kit on it? More practical than nitrous, don't have to fill a tank or hit a switch. About the same $$$ for used.
I know you're excited about the NO2 and wanted encouragement, but us old farts are only going to rain on your parade with our fuddy-duddy common sense. Actually, A B1200 wouldn't be much more insurance-wise than your 600, they're both "standard" motorcycles... but if you are young, then you're gonna get hammered on just about any bike insurance.