Can't help with the tank question but I traded up from an SV to a Firestorm.
Great bike
, had CCC cans on mine and that used to set off car alarms too
Used to handle OK for me too, never found the front end to be an issue as has been mentioned. Took it to St Mont Michel last summer, was getting about 110 - 125 miles between fill-ups cruising at ~120
Was a little taller than the SV but didn't feel too much heavier