I have seen people post about using heavy wall PVC pipe and that could make a restriction in the system before the air filter.
I like to use exhaust pipe for the connection. It has a very thin wall thickness and the filter will be the only possibility for a restriction.
Last I checked the thick walled PVC pipe is actually measured by ID while exhaust pipe is measured in OD. So the heavy walled PVC pipe is most likely actually slightly larger ID than the exhaust pipeing.
If I were going to buy a filter set up for my truck I would go with the AFE. IMHO it's the best compromise between filtration and flow. IMHO the PG7 would be an excellent choice for daily driving while one of their better flowing ones would be great for the strip or dyno runs.
The Donaldson filter that everyone likes to run because tymar uses it is a medium to heavy dust filter so it doesn't flow as well as it could but does filter well. That being said I have seen some intakes with a very fine dust in the intake pipes. That truck had been offroaded a fair bit though. Though not known for their filtering abilities a K&N would be a good competition filter. They flow very well. Personally I like the oiled filters better for filtration. As the air zig zags through the media the dirt particles can't make the sharp turns so they hit the oil and stick. IMHO they are better at filtering IF the media is thick enough. If it's thin enough to see through it, well then obviously it's not going to filter as well. IMHO oiled foam filters are hands down the best filtering however due to being so thick they aren't as good at flowing unless you use a very large filter.