I have been to a grand total of three IRRA®-run events. One was the Fall Brawl of two years ago (where I was a hazard to competitors and spectators alike). I got there via my local track (Fast Tracks in Bechtelsville) which had a very nice Retro group. The guys were having what looked like a great time and that caused me to reverse my original reluctance and join the fun. The Puppy Dog was my choice of motor. After the usual mucking about, I did well with it but soon switched to the TSR or Falcon as I got tired of losing ten feet every time there was a track call (and there were many as we were chronically short of turn marshals). The Retro Hawk eventually eliminated the PD from my program.
As far as the Puppy Dog is concerned, the potential for mischief (perceived as well as actual) was its downfall in my opinion. Yes, accusations of personal biases have been raised but the fact remains that a large number of participants expressed little to no confidence in the system as it was. No matter which side your on as far as that goes, bear in mind that Hitler's dog liked him a lot.
SImilarly, the elimination of the 4002FK has elicited protests from some, and given the very limited application that motor has in IRRA® racing I suppose I see why. But if I may digress slightly, I offer the following tale.
I moved back to my old hometown here in Upstate NY last August. I found the only racing going on was either a Hardbody group or a spec sportscar class requiring an all-steel T-Flex, a PS4002FK, and a Parma Ti22 body. So that's what I race locally and, except for that damned motor and its tendency to come apart, the class is OK. If I were part of a rulesmaking body (and be happy I'm not) the PS4002FK would be about my last choice for a spec motor.
NOTE: I have long advocated the Puppy Dog's rehabilitation as the sole motor in a no-seal class. I've received no support from anyone on that idea but I feel obliged to mention it if for no other reason than personal consistency.