stock sway bar sizes

[PGT]

Of course they do, but don't minimize the swaybars either. I had urethane bushings on the stock front bar and the JDM 20mm bar.....the bigger Perrin bars were harsher by a noticable amount.

[Waxiboy]

Here is my 2 cents from I know from RC racing (they should be the same in principle for real cars): Anti-sway bars work when there is a difference in side to side load. The bar functions by trying to equalize the L-R loads. Front and rear load changes should have no effect. So in theory, when you drive over a speed bump (assuming both L & R tires hit it at the same time), the sway bay will have no effect.