Exactly where to measure is tricky (admittedly, in my limited experience). For example, if you mean by your reference to "at the lowest point at the center of nose of the car" the painted fiberglass section, that actually is a little lower on my car than both the metal brace at the front of the radiator and the apparent "floor area" of the underside. What I have done is chop off a ruler at about 5" and started measuring many places. One place I have also measured is from the ground to the lowest point of the frame right in front of the left front wheel. My concern is not so much messing up fiberglass, but having some frame or other key section grab onto the payment and really do a number. I did see a racing MKI for sale at Hillbank earlier this year with 225s in front and, I agree, they look a little large, but what's interesting is that in my Owner's Manual they are listed as the front tire size and, on balance, I'll take the extra clearance. Anyhow, I will work on this over the next month and report back my progress, or lack thereof. I am really enjoying this discussion!
/s/ Chris