I occasionally get asked about splashing other cards in CI7 (special report was the latest one, but 24/7 is a good example too because it definitely has its uses). CI7 currently uses most of its influence on the combo. 1 power shutdown, 2 SFSS, 3 SFK and 3 JH costs 10 influence. This leaves 5 influence for a) 2nd power shutdown, b) 2x GFI and c) reuse. If you want to add something else, you have to justify it as more important than any of these cards.
a) 2nd power shutdown. This is absolutely crucial. I can't tell you how many games I've lost because I haven't found one of these while the runner keeps getting accesses. Unless your supposed card increases consistency some other way, it it wrong to cut this.
b) 2x GFI. Saves you from losing when the runner steals 3 agendas, letting you force them to take one more access. Probably the most likely candidate, but I doubt 24/7 is really worth the trade here, especially as it still isn't enough influence to cover it.
c) reuse. Saves you from just losing when they vamp you, and even better, if you have enough cards you can reuse into double biotic and actually win the game. Vamp is already your worst enemy, and siphon is up there too. At 1 influence this is a steal, and you'd be hard pressed to find a better card for the slot.