theyve got pretty decent inline fans at home depot in 4-6-8" sizes. only like 25$ ,30$, 40$ respectivly
i use 1 6in blowing at 250cfm for fresh air 1 6in on one end of my 600w and an 8in on the other end. then the whole room is vented out with a window fan. it keep temps in each of my boxes...