I'd start with this:
It's a BTR39, (rear sway bar) from... Whiteline.

See if it makes the car handle the way you want it to, then maybe look into the front one from same. The rear bar will reduce understeer and keep the car alot more flat in cornering.
The front bar is a really stiff mother. The car will corner absolutely flat, but it will make the ride very firm in side-to-side bumps (left-right), road irregularities. This can make a car feel twitchy and unsettled on regular roads, but razor sharp on a race track.
The front bar will probably make the car corner even harder on a race track smooth surface, I don't know yet myself. Haven't tried my big front bar (BTF38) on yet on the Camry, or in any past FWD car.