EXAMPLE:
i have these two characters in play...


1. Roy Harper <> Arsenal:
Exhaust a Teen Titans character you control >>> Roy Harper gets +2 ATK this turn.

2. Connor Kent <> Superboy:
Exhaust a Teen Titans character you control >>> Connor Kent gets +2 DEF this turn.


QUESTION:
for each individual tt charcter i exaust, can i combine both arsenal and superboy's above payment modifiers or can i only choose for one of the two effects to take place.

One character for EACH effect, sorry. :)

No. When you pay a cost (the left-hand side of an arrow) for a power, you're only allowed to generate that effect once.

Think of paying costs as spending dollar bills. Even if i'm selling a candy bar for a buck, and a box of milk for a buck, if you have one buck, you only get the candy bar or the box of milk.

oh, the arrow. now i understand. thanx

I cant find anything on this but, Lets say I go Roy Crazy any somehow I get my roy stunned, but I left a Roy effect on the chain. Does it check his printed attack or his boosted attack?

It checks Roy's ATK at the time the effect resolves. Roy doesn't lose his ATK value when he gets stunned. And I'm pretty sure the effect would still allow him to increase ATK if there were more 'Roy pumps' on the chain after Roy gets stunned, but I am not one hundred percent certain on this point.

Could you give me an example of what you mean?

Use Roy Harper's effect 3 times (+6 ATK). Let it resolve.
Activate Roy Harper. Use Roy Harper's effect once. Pass priority.
Opponent plays Overload on Roy Harper and passes priority.
Player passes.
Roy Harper is stunned.
Both players pass. Roy Harper gets +2 ATK (I think)
Both players pass. Roy Harper's current ATK is checked (it will be either 10 or 12, depending on if ATK boosts can be used on stunned characters. Again, I am pretty certain it will be 12) and stuns target character if the character has an ATK less than Roy Harper's ATK.

Roy can continue to recieve ATK modifiers after he is stunned, but in your above example I'm not sure where the extra +2 is coming from.

Roy had a 'pump' on the chain that was chained to by Overload.