Agree entirely with everything Jazz just said - was just typing similar post but got distracted. My pump, like the ones on eBay was <£5 and no radiator / fancy coolant. You'd have to try hard to spend more than £25 on the cooling system I reckon. Aluminium for the mount brackets <£10.

I have also inadvertently left my pump off, and yes it warms up a bit but it seems no harm done.

If you want to invest money on a better controller use the money from the S-pid to get the better VFD. Even so, there are many many people who have used the china VFDs with no problems (myself included, got two now) and they've recently changed the design so presumably it's better. Obviously people only post on forums about the VFD if they have problems with it. Jazz has had bad luck with them though I believe...