Arouse the DAMPFHAMMER!
Definitely, those are a nice upgrade if they come for free or at least less then the cost of a party with your friends . The difference is in the range of a few ftlbs in some areas, which is by far not the case if you put in DIC (drop in cams), which are cams which don't need a valvetrain upgrade like stiffer valve springs, here you will see some more of this ponies all over the revving range (TODA A2, DC DIC, ...).06-08 tsx Intake cam seem like an easy upgrade as well sinse you'll already be in there taking the vtc off.
Yes, the weight will eat some ponies under transient situations where engine speed increases significantly. It is the inertial mass of the balance shaft causing the power loss there. If the engine speed is stationary, it has no influence in power beside the friction of the balancer drivetrain.although I think it’s been argued the loss in weight by switching to the PRB oil pump is good for a few hp/tq but I think of it more as a higher rpm capability modification.
Every weight, which need to get rotated costs under acceleration some of the ponies. As thumb rule, you get a double payment request for the distance of the mass, connected to the shaft and you get a single payment request for the shaft speed (principle of angular momentum).