Where to find a gen II chassis stiffener?

Priuszilla.com though you might be better off purchasing a new front and rear roll bar. Somewhere around 20mm-24mm I think was the sweet spot for most users here. All Prii’s except the Touring had 19mm, the Touring has 20mm.

I’ll be grabbing a 24mm TRD rear and a 24mm whiteline sometime next year for my Touring

 

A roll bar connects to your suspension. When your suspension compresses in a turn the roll bar literally twists to keep the car from leaning over too much. Hence “roll bar” or “anti rollover bar”. The larger in diameter the bar the less the car leans but if you go too large you’ll suffer from poorer handling. IMO that’s the first upgrade you want to do when it comes to chassis stiffening. Other things like strut braces and under braces won’t have nearly the same effect.

 

If you want better handling, your order of operations in improvement versus cost on the Prius is:
1. Better tires, wider tires (I have 205/55R16s Michelin Premiers and can attest to much better handling versus Yokohama 185/65R15s).
2. Front and rear swaybar upgrades, most do an aftermarket 24mm in the rear and a 24mm (IIRC) in the front from a junkyard corolla/matrix. This is a planned upgrade for me.
3. Coilovers/struts and shocks, Front strut bar, mid chassis stiffener plate, (exactly which one will improve handling will depend on exact circumstances - debatable. Coilovers can improve handling the most but are also the most expensive).
4. Other stiffening bars

So I would recommend looking into upgrading #1 and #2 first.

 

I think when it comes to chassis stiffeners your best logical bet for the Prius is a front strut bar. Other than that I’ve seen mixed reviews about other forms.

You definitely want roll bars and suspension. Not sure what model you have but my Touring already has the tire size Kevin is talking about. I might add that checking alignment will help in case your toe, caster and camber isn’t where it’s supposed to be.

I’ve heard negative camber is better for drivers that like to turn harder and faster. But it will increase tire wear and isn’t the best for straight line acceleration.