As I understand, some of the remaining issues are bound to be about cards with a heat cost.
I think that the heat cost of cards played should be paid first: you should not be allowed to play a boost before having paid for them.
Now I believe that the cost of those cards *can* be paid after using cooling effects whatever the source of the cooling.
I think the rules make it clear enough that you must pay the Heat cost of the played cards if you can.
A problem though is whether someone should be allowed to play a upgrade card if he cannot pay for it.
There clearly are situations where you would want too.
1) because playing an upgrade card degraded into a "+" card is actually the best you can play
2) because playing that card is the only way to avoid a cluttered hand
Personally, I think that neither should be allowed.
I also think there is no contradiction with the cluttered hand rule (at least for the French version I read). The cluttered hand rule states that if you cannot play enough cards then you must play all the cards that you can play and complete with Heat cards. So if we accept that we cannot play upgrade cards that we cannot the heat pay for then the cluttered hand rule remains clear enough.
So the only real problem with cluttered hand would be if you have more than 3 upgrade cards in hand that you cannot play or less than 7 cards in hand. If that was to happen (may be possible in a championship ?), you might have to allow player to play upgrade cards as dead weight (like a heat card) in a cluttered hand. Because in such a scenario in speed 4, you could have 4 unplayable upgrade cards and 3 heat in hand which leaves no solution.
I think that the heat cost of cards played should be paid first: you should not be allowed to play a boost before having paid for them.
Now I believe that the cost of those cards *can* be paid after using cooling effects whatever the source of the cooling.
I think the rules make it clear enough that you must pay the Heat cost of the played cards if you can.
A problem though is whether someone should be allowed to play a upgrade card if he cannot pay for it.
There clearly are situations where you would want too.
1) because playing an upgrade card degraded into a "+" card is actually the best you can play
2) because playing that card is the only way to avoid a cluttered hand
Personally, I think that neither should be allowed.
I also think there is no contradiction with the cluttered hand rule (at least for the French version I read). The cluttered hand rule states that if you cannot play enough cards then you must play all the cards that you can play and complete with Heat cards. So if we accept that we cannot play upgrade cards that we cannot the heat pay for then the cluttered hand rule remains clear enough.
So the only real problem with cluttered hand would be if you have more than 3 upgrade cards in hand that you cannot play or less than 7 cards in hand. If that was to happen (may be possible in a championship ?), you might have to allow player to play upgrade cards as dead weight (like a heat card) in a cluttered hand. Because in such a scenario in speed 4, you could have 4 unplayable upgrade cards and 3 heat in hand which leaves no solution.