My Dust Collection unit is the 2HP model from Harbor Freight, and I have to say, it's been worth every penny. I got it on sale for $159 (reg $229), and I think it's hard to beat it's performance for the price.
I have it connected with 4 inch thin-wall PVC sewer and drain pipe and it works really well. I have a blast gate at every machine, and can only have one open at a time.
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