I can not answer the power question as the bike is to long for most dynos (Or so that is what I have been told). In comparison my TP 113" will walk the 100" with the charger hard out of the hole up to around 90 mph than the charger starts to turn on.
Cost is another one that can't be simply answered. Are you installing it? Having it installed? Polished finish? Satin finish? Billet version? Single or dual carbs? Changing pistons for lower compression?
When the charger was initially installed on the RT 100" it was installed just as the motor came out of the crate. It eventually started spitting oil real bad which was never determined if it was a charger issue or something else. The second motor had low compression pistons installed which allowed for turning the charger up to make more boost. The charger was removed less than a year later than the bike was sold. So I can't say how long it would have held up. While it was installed it worked well and the bike never left anyone sitting because of the charger.