For comparison sake, keep in mind the TransGo kit comes with 10 new springs, 3 new valves, 3 new check balls, a restrictor orifice, and 4 different-size drill bits to open up 7 tiny passageways. This kit retails for around $250.
My 05 IPT Valve Body consisted of the following changes (note 05-07 VBs are the same part number):
Resistors Added: Zero
Holes Drilled: Zero
Springs Swapped out: Zero
Springs Added: One.
See attached photos to see the contents of the one lucky valve bore, where that shorter spring is added inside the bigger stock spring.
Also note that IPT removed the 4 little filters found deep inside the stock valve body. TransGo says to keep these 4 filters installed, and my gut says the same thing. They are each about double the size of the banjo bolt filters.
$769 buys you one spring, installed, and four filters deemed a good idea by Jatco and TransGo, removed.
But if you go to do this spring install yourself, be careful! You have to take apart the valve body to get inside these valves. There are 5 tiny check balls and 3 springs in two lower valve body decks. If you lose or misplace these upon re-installation, you're pretty much screwed. I spent a lot of time learning how to do this before doing it. You don't need to be a mechanic to do this, but you might want to have an experienced friend help you out the first time.