While I don't have as large of motor as you are proposing I run a BDS scoop and 2 K&N oil spray air cleaners. This scoop is the quite a bit larger than the traditional "Hilborn scoop". It's great for catching large dragon flies. haha
I have just over 19k miles now and no problems at all.
You have to remember that there is really very little air going into the motor when cruising. It only takes 50-60 hp to go 60 mph unless it is really windy or you have big truck. I cruise a lot in the rain too and we do get on gravel roads occasionally. Still the dirt I get out of the air cleaners is very small.....hopefully it is not going into the motor. haha These K&N AC are pretty good I think. They can get real dirty on the graveol roads but so do my unblown friends with their BBC's and 383 SBC's with the larger K&N air cleaners. We compare notes all the time.
I fail to see why an EFI doesn't take into account the mass of air coming into the system. I can see WOT throttle being a bit choked with the small AC's but I you are going to the track just take them out if you want. I would think the EFI sensors would compensate for this. If not stick with the carbs. Mine sure work great. 5 deg F to 103 last year and no adjustments anywhere. I even got a little snow in the scoop this year in Jan.
And BTW I've looked at most of the popular blower EFI''s that go on x-71 style blowers. I've yet to see one run well out of the box. If some has one or has experienced this, I would love to hear all about it.