I'd say, based on testing I participated in... that you could just use the stock airbox and filter for optimum performance. I know the claims made from all the main manufacturers (albeit NOT with a 2013+ SHO). Here's the data I have:
On the day when 4DR and I used my SHO (stock tune) to test 3 sets of the PPE downpipes on the dyno at Black Market Racing/Full Race (catted, Non-catted, and thermal coated catted)... (9 pulls-3 per set) ...We also did the following... in one pull we completely disconnected the OEM airbox from the intake tube (the saxophone tube going to turbos) and set it aside so we just had the tubing and no filter or CAI. We had the hood up, a big cooling fan on the motor, and back to back dynos with the same operator. temp was 79 and humidity was 30%
Result... less than three HP difference (same forTQ) between OEM CAI and filter and no filter or CAI at all.... 2-3 HP is not a significant change and lies within margin of error. I believe that any restriction to air flow in the SHO is after the filter. We know it can use more air than it does bone stock... we got 17HP increase with the PPE DPs over stock DPs with or without the CAI/filter. Currently I believe the stock CAI and filter can deliver all the air the engine can use.
If you want some more sound from under the hood or like it as eye candy... go for it, nothing wrong with that.
But currently I can't personally recommend anything over the stock box based on the data if performance is the issue.
If you want better filtration try another filter. I hate oil filters... I bet you will too, hassle and oil gets where it shouldn't.
That's my 2 cents... sorry to seem like a rant.