The original Stealth featured a very small jib, after a few months we had owners asking for more performance, so we brought out the Stealth R, this had a bigger jib and longer daggerboards, we offered the upgrade to all existing owners at trade price, they all took us up on this, so all Stealths are now Stealth R's, although they can enter handicap races with the old set-up, and indeed do, but only when there is strong wind. When the F16 class was concieved we decided to change the boat to fully optimise the rules, thus the F16 was born. The main differences between the F16 and the R, are that the F16 is 20cm wider and some jib area was moved to the mainsail.
I have not been active with the 16 since 2001, when we won the Uk cat racing champs, with a Stealth R, 2002 we were busy changing the 16 and in 2003 we were busy with the F18HT and moving to Wales.
I have not raced the F16 properly since we bought it out, however we will be racing one this year and hope to repeat our 2001 effort.
I can tell you that the Stealth R rated 102 in 2001, (there was a carbon mast penalty then), and we found that it performed to this rating well against all boats, Spitfires included. I can also tell you that the F16 rates at 102 now, and that it is significantly faster than the old model.
My opinions of our boat and the F16 class are of course very slightly biased, as we sell them, as are Dermot's of the Spitfire as he sells them.
There are 32 Stealths in the UK, mainly Stealth R's with 6 of them F16s, unforunately hardly any of them travel to events, mainly club sailing.