Congrats on the 340k miles.
You can do as you like.
Your ride, your choice.
No need to ask members for permission.
However, if you really believe the combo of seafoam is going to make the difference and/or along with, changing the R16 resistor....
On many discussion forums we have have read of the "free horsepower upgrade" available to those with M102 and M103 motors by way of removing or changing the value of the R16 ignition reference resistor. Many who perform this simple modification (generally removing R16) claim great results using...
www.benzworld.org
And this one is a 20yo thread too.
Not much else in m103 m104 power upgrades, unless you add another few 00s to the 50 you have.
But then, for that kind of money, you can get yourself a nice replacement MB, latter model and fast(er).
Better $ spent gathering a few acorns for this ride, imo.