Stopped off at my local RS and returned the Chevelle, and picked up a 2nd Orange GTO Judge.
The 2nd GTO is everybit as good as the 1st one, no stutter at all.
The guy at the counter even asked me why I was picking up another SE when I had just returned 1, I told him about the stuttering problem and he just shrugged and went through the transaction.
Best I can piece it is this;
The 1st generation SE was the Initial-D Savannah with part number 60-7026. The numbers have progressed and we're now up to number 60-7040/7041, the Pontiac GTO Judge
Now, my opinion is that the GTO line was rolled out at the same time (maybe even a little bit sooner) as the rollout of upgraded ZipZaps SE PCBs. From that point on, any newly produced SEs would benefit from the upgraded PCB (explaining how 'old' Initial-D Savannahs seem to be fixed)
Which begs the question (as Az already said) "How do you know which ones have the new PCB?" Unfortunately I haven't seen any defining characteristics and I wish I'd have seen your post about the endbells Az, before returning the SEs to RS
The only suggestion I can make at this point, if you want to buy an SE that doesn't stutter, is to stick with the highest part number possible. Which means the Chevelle, Starsky & Hutch and ESPECIALLY the GTO...I would go so far as to recommend finding the Orange GTOs (I've been 2 for 2 with getting good ones, whereas a blue GTO proved to stutter), perhaps the Orange ones are freshest off the assembly line using the new PCBs.