@LinchpiN
I used to have the same accelerator (recently sold via eBay) - and I never had any heat problems at all.
It didn't need a fan or heatsink, and I didn't leave the trapdoor cover off.
The Apollo A1230 that I had briefly before that, however, was a different story... instability is too mild a word :-)
The 030 is never going to be as fast as the 040 - but it is more compatible; many games and things will bork at an 040, but not 030.
The Blizzard A1230-IV can be disabled by holding down the "2" key when booting, helping compatibility.
The FPU is only useful - as pointed out already - for some flight simulators; also there are some rendering packages and things (Aladdin, Tornado, ImageFX, Vista Pro, etc.) that have optimised FPU versions or modules. Additionally, there are fractal generators that make use of the FPU. Not a big boost, but can be useful if you're using the calculations on a regular basis...