I have some TSW Nurburgring wheels on my 06x sedan. They are a +45mm offset. Wheel specs are 19x8.5.

I was wondering if I can throw on 15mm spacers on the rear and be flush or atleast a little poke with the fender? Not lowered I'm at stock height.

 

dont wonder. expect.

with those offsets you will NEED the spacers. hell id bump them up to 20mms even.

 

This is how it looks right now:

 

i was really expecting that to be a lot worse when i read your offsets..
if you lower the car AND add the spacers expect to rub on the fenders (youll need to roll them)

 

15mm will be fine...you can also go larger.