I don't know about the risk of blowing a seal with a new valve body. (BD could tell you) However, I have had a BD low stall torque converter, BD valve body, and BD linkage which increase the pressure at the right time on my 99 for over 4 years now.
BD put it on their Dyno and I was putting out 360 HP and 1000 FTLBS torque.
I have an Edge comp and other goodies on my truck and with the BD mods I have not had one single problem with my transmission.
I went across the US, through Canada, to Purdue Bay pulling an 8,000 pound camper trailer. Bought a bigger trailer, 10,000 pounds and pulled it up and down the East Coast with no problems.
BD was great to work with and stood behind everything they sold me, even when I messed up the install through my own stupidity.
I still do get some excess heat but I just pulled and cleaned my radiator of gunk from the blowtube. Don't know what that is going to do but there was a lot of gunk.
My truck has about 170,000 and the BD transmission mods have held up well. I put them on with less than 20,000 on the truck.
I know this was a long story but I can't say enough about how pleased I have been with BD products and people. And no, I do not work for them. They did me right and I would have sold the truck because of the piece of junk Dodge transmission if they had not helped me.
Short answer you can increase your HP without overhauling the transmission with, a new valve body and torque converter.