That depends on where you live (weather, local codes, neighbors). If it’s not too cold and you are allowed to vent outside, that it’s OK. You will get rid of the noise, save some space, and avoid re-introducing the air to the workshop space. You can take the entire system outside and build a big box and vent it outside. Make sure the collector unit is well-grounded. You can also try and run 2 sets of pipes to each unit, i.e. dust exhaust and fresh air intake. However, keep in mind that you will create a negative pressure environment, so make sure that your work area will not have any problems under that (no combustion gas-fired equipment).
Some people say that large stationary units are still better than portable dust collectors. So if you are still thinking about buying one and you don’t have any space issues in your workshop, moving the collector outside will not be necessary – high-quality cartridge filters in modern cyclone systems do their work great.