I see what you're saying, it's just hard to explain how zip ties (if you have them nice and tight) would move around more than the fan mounting kit (basically round zip ties). They are virtually the same thing, the mounting kit just has a seperate end to clip on. I've done both methods on more than 3 radiators each.

The way I see it, if you're zipties will end up causing damage to the radiator, the mounting "zip ties" would do the same. The only feasable option at that point is a real mounting bracket of some sort.

 

The ties from advanced auto that are made for this will not move. That is what we use at school for all the race cars. That includes are, stock cars, sprint cars. dirt track cars take a rediculous beating and the cans are fine and never move. the Arca cars see well over 100 mph, close to 200 and they are fine. Im pretty sure if they will survive this, they will be fine on an evo.