You won't find any difference in performance until you get into high-performance situations. Think of it as having V-rated tires on your car. When I had my Volvo 850, I had both V and H rated of the same tire at various points and noticed no difference for what I was using it for (regular driving where the fastest I'd go was 65mph on an interstate). Had I been driving at much higher speeds or using it in racing of some sort, the V-rated tires would have been beneficial. Think of big calculations, CAD, etc. as being your "racing situation" here.
That being said, I do have an FPU in my Classic II but have never had a situation in which I've had to use it. It came with the machine, unbeknownst to me when I got it as a 15th birthday gift from my cousin many moons ago, and I've always wanted some excuse to use it.
(Also, I only buy H-rated tires now...has saved me lots of cash...could get away with lower but I have yet to see Michelin Primacy MXV4+ at a lower rating, and I swear by that tire...)