From my experience the B&M kits seem to make the shifts harsh all the time whereas the Transgo kits give you a firm but softer shift at part throttle and harder shifts at full throttle. They're much more friendly street kits.
I've always used B&M, I'm sure others are fine too. Remember a higher stall convertor will absorb ALOT of the shift harshness
If you are a tightwad like me you will hit the Google and download as many th350 shift kit instructions as you can find and commence to reading . You can do a lot with some well placed drilled out holes in the separator plate and some spacers from whatever you want or can find(washers, cut off pieces of tubing, nuts.) This is what I did for my 2004r on a budget. I even found some places where the gurus had some how-to on spring swapping in the vb. Might even figure out which check balls can be deleted. Not for everyone, but I definately have more time than money and don't mind a trans fluid bath a couple times getting the thing to shift "just right". http://files.dpbrands.com/bm/instructions/30262.pdf http://news.compperformance.com/Instructions/350000.pdf and some how to for the shift kit from transgo https://www.chevydiy.com/gm-turbo-350-shift-kits-and-performance-modifications-guide/
I just helped a buddy put his first T350 shift kit in and it was a TransGo. Went in really easy except for the welded cross member that blocked the back pan bolts and the pan from being removed. I've probably done 50 though this is the first one in 20 years. They were mostly B&M and they all work pretty much the same with minor variations.
