I have a second storey bathroom with a toilet and sink at the back of a narrow bathroom... and a tub with a shower on the left in front of the toilet. Because the Sink is so small I would like to move the toilet to where the sink is, take out the tub, turn the shower head around and put a shower where the toilet is. Then I can put in a longer sink and cabinet where the current tub is. What plumbing and venting issues will I have to deal with?