I am currently working on modifying the Harbor Freight 97869 model which is the one you are speaking of I believe. It was about $155 on sale with 20% off after taxes.
It was a great deal...although, I think you need to consider it incomplete when you first get it. I am adding the Wynn Environmental 35A cartridge filter (
http://www.wynnenv.com/35A_series_cartridge_kit.htm) to it and also making a cheap modification of the Thien BaffleThat purple monster of Vaughn's is a Harbor Freight 97869
https://thehomedweller.com/best-dust-collectors/ he has painted up. He has gotten excellent results allowing him to go weeks without even touching the filter, and when he does have to, he just shakes it or blows it with air externally to make sure the fines are not caking up on the inside which he says is so minimal he could go longer without touching it even.
The 35A filter is safer (.5-1 micron depending on the one you choose) and will increase your CFM capacity a bit over the 5 micron bag that the unit comes with originally. You may want to consider changing out the bag on your jet as well since 30 micron is not so good.
According to everyone I have talked to and everything I have read, these machines are the best bang for your buck when coupled with the cartridge filter (less than $350 together depending on discounts, taxes and the filters shipping cost). This is a FAR FAR CRY from the $$$$ you will have to fudge out for a name brand DC with a cartridge filter already installed or with an aftermarket addition. Especially when you consider the HF model has been getting so many great long term reviews. The 97869 is an upgraded version of the previous model with larger impeller, 5 micron top bag (30 micron was on the old one) and clear bottom bag...otherwise the same for the most part. The older version with modifications such as I am doing, is still getting good reviews years later.
Here is a video of Vaughn's again, the first time around with a collar that he removes the second time around so there is no need to worry about what the collar is. Look at that cyclone action with nothing dropping out of the filter the second time around:
http://workingwoods.com/misc%20image...lar%20Test.wmv
Should be perfect for your shop as I consider it more than enough for mine at 288 sq. ft.
All the best, Mardagora
ERP based on Java