I wouldn't touch anything. The springs are going to settle and will change the fender gap all around. Worst case you could remove the isolators on the high side.
Dealers usually write the mileage down on the work order/paper work. What was your mileage when you drove off the dealership compared to when you dropped it off?
Looks great. I had an apartment at the corner of 7th and 51st this winter while I was working on a project in the financial district. Very expensive to live in NYC. A hamburger was $25. Thank god for an expense account. Yikes!
My replacement pcv for my 01 gt came with 2 elbows and a cap as Speed545 described above. I used a hairdryer to soften the plastic and it slipped right on.
Cars are a depreciating asset. IMHO, adding power mods to a car enhance the enjoyment for the owner and adds very little to the resale value. They may get a few extra bucks but not much more. I would doubt if an insurance company would pay out any more than book value if a car was totaled...
According to accufab's website the 70 and 75 tb and plenum combo flow the same volume of air. With your mods I would assume almost no difference between the 70 and 75 tb. If you plan additional mods just get the 75mm tb.