Video: How a bigger rear sway bar can unlock more speed

Yes, definately in a FWD car. 

I love my upgraded rear bar, has done wonders for me in my FWD companion for autocross & track. Handles like a dream, and sometimes I get a little slide as a treat 

Great video and explanation, the stiffer rear bar should offload the heavily loaded front tires during cornering. If there is an option, go for the adjustable bars - you can get another setup possibility.

I have upgraded both front and rear sway bars with adjustable bars from Whiteline on my FWD 7gen Celica and it is one of the best price to performance upgrades for the suspension. I like to run the front on soft and rear on stiff to aid understeer but still keep front camber in check. 

The only downside I have found is that after time, the polyurethane bushings start to squeak even though they have teflon coating. It is not loud and it's not possible to hear during driving in my case, but I have read about worst cases. A re-grease should solve the issue in most cases. 

It would be nice to see a test with adding also a front bar on the GTI - would it be faster? I didn't have the chance to test that out yet so it's an interesting thought.

I was surprised to find that the sporty versions of recent Toyota Camrys use 25 mm solid or 25.4 mm hollow rear sway bars. I haven't seen anything that big since my '89 SHO. However, after 150 k-miles the rear doors rattled.   C R Hammond

I ran two rear bars on my Rabbit GTI–the stock piece plus an aftermarket one. It rotated nicely. :)