I'm not yet doing a full review, but just thought I'd get a few initial thoughts up. The kit comes with 3 springs and a new, slightly longer firing pin (to ensure reliable ignition). Install was easy and only took ~5 minutes. Toughest part was getting the sideplate off of the relatively new 642 that I rarely use. 
I need to get a trigger scale but, typically J frame DA pulls tend to be in the ~12-15# range. Mine felt every bit of 12#, and I wouldn't be surprised if it was a bit heavier. Apex Tactical quotes their J frame spring kit at ~8-9#. I wasn't sure what to think about that, as I'm of the opinion that over ~7# is overkill, defensive gun or not. 9-12#+ just seems ridiculous. However, I have to say I was pleasantly surprised. I would estimate that the pull was definitely reduced to 8-9#, probably closer to 9# and feels smoother. I was instantly reminded of the Ruger LCR trigger, as it is a smooth and considerably lighter pull. Overall, for the ~$30 of the spring kit, I highly recommend it! The gun is a lot more bearable now.
Next step is sights, which will suck for the wallet, but it's the right thing to do. Basically large sights milled/dovetailed into the frame and barrel, which is pretty much a $200-250 job. Most people probably think it's crazy. I think stock J frame sights are crazy stupid, and I eventually need to correct the problem. Here's an example from D&L Sports:
I need to get a trigger scale but, typically J frame DA pulls tend to be in the ~12-15# range. Mine felt every bit of 12#, and I wouldn't be surprised if it was a bit heavier. Apex Tactical quotes their J frame spring kit at ~8-9#. I wasn't sure what to think about that, as I'm of the opinion that over ~7# is overkill, defensive gun or not. 9-12#+ just seems ridiculous. However, I have to say I was pleasantly surprised. I would estimate that the pull was definitely reduced to 8-9#, probably closer to 9# and feels smoother. I was instantly reminded of the Ruger LCR trigger, as it is a smooth and considerably lighter pull. Overall, for the ~$30 of the spring kit, I highly recommend it! The gun is a lot more bearable now.
Next step is sights, which will suck for the wallet, but it's the right thing to do. Basically large sights milled/dovetailed into the frame and barrel, which is pretty much a $200-250 job. Most people probably think it's crazy. I think stock J frame sights are crazy stupid, and I eventually need to correct the problem.
Here's an example from D&L Sports:
