Did some research, because still after reading this thread through 2 times, wasn't sure should dipstick tube be changed or not.
Old WRX uses item 15144AA011 according to http://opposedforces.com/parts/impre...ystem/oil_pan/
New WRX/STI and also Legacy uses item nr. 15144AA100 http://opposedforces.com/parts/impre...ystem/oil_pan/
I don't have a real life picture comparing these two, but according to these links, I will definitely change it also.
So my setup will look like this:
Oil pan 11109AA151
Oil baffle 10915AA010
KB oil pick-up
Since I already purchased an OEM 11mm oil pump, I'm going to test it. If oil pressure readings are getting to high, then I'll change it for 10mm, but my builder and Celtic Motorsport said that I should be good with it, so we'll see.