Where do you guys get your blow off valves, where's the best place to install it and do I have to do any tuning to compensate for it?

looks like the turbo oil line was filled with a plug and redrilled for higher psi, but less flow, is this normal? and for cleaning the old lines out and oil cooler does a mix of carb cleaner /degreaser /water sound good?

I know, asked a million times... But I can't find my answer.   What was the stock size? 3mm, 3.2mm or 3.5mm?   Also, any idea how much length I'd need? All emmisions deleted.   Thanks!

lost a few of mine when I got headwork done. shipped to 55128 just need 2