Jamas, the "pop/clunk" sound that you are describing does sound like a cladding issue. When I had my larger tires installed I had some horrible noises until I could get it home and trim off a small triangular piece of the front cladding in front of the wheels. Have you always had the larger tires, or are they new? If they are new, have you trimmed the cladding any? Before the trim my cladding/tire noises would happen when the wheels where turned because that's when the tire contacts the point of the cladding in front of them.
One way to tell would be to let someone drive the VX (I know, I know...SIN!!) with you walking along side to see what might be rubbing.
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