I could agree with that. I wouldn't mind having 1-2 beefed up as much as the 2-3 is. I'd recommend it a bit firmer if you like firm shifts. I do and I would like it a little firmer.
And I can agree, higher mileage 4t65e's often shift like crap. Our impala recently developed slow shifts (116k), it needs help for sure. Its probably how the GP with 171k shifts. The up shifts used to be like you had a shift kit before it got worn out.
Don't even get me started on how it downshifts stock at about 3/4 throttle, so sad... I was gonna pass someone in the impala and I was waiting...and waiting, come on! lol. Almost a safety issue in my book. The shift kit will take care of it, just have to find time to put it in.