Transgo offers the best shift kit out there and their kits usually allow you to choose the level of firmness you want.
Transtar is a company you should be able to get a new plate for the valve body, or a complete valve body ready to go.
Can't say I've ever had any issue with a shift kit that I've installed over the years. But a stock shifting TH400 works fine and will be trouble free forever almost with a little maintenance.
