i was just looking around buying some pillar gauges and i was wondering if which would be best between the preturbo or post turbo pyrometer if not both....

You want to put your pyro pre turbo that way you know what kind of temps your turbo is seeing. Secondly this type of question has been asked many times, try doing a search this will allow you to get the anwsers you are looking for when the topic has already been covered. Have Fun!

I found a very helpful thread in the DIY section that helped me a lot. I forgot exactly where it was but it had helpful tips and pictures too

Search for the "Hoot method"