Best bang for the buck mods for improving high speed handling?

There used to be many versions, only this one is left Prius Accessories and Hybrid Car PartsJuiced Hybrid's Prius Chassis Stiffener Kit (Fits 2004 to 2009) - Prius Accessories and Hybrid Car Parts

 

The front upper strut bar did the most for my 06'
2nd was the underbody mid section stiffening plate
3rd was the 17" 45 series tires and wheels

 

1. wider, better tires, 2. aftermarket corolla/matrix Progressive rear sway bar (or TRD), 3. front oem corolla sway bar. the sway bars make a tremendous difference on non-touring models; I expect they will help the touring too. a used front sway bar is cheap, but installation requires the engine cradle to be unbolted from the body, or the steering rack to be removed. its not a bad job if you know how to work on cars. rear sway bar is very easy to replace.

 

what kind of tires do you have? when was the last time it had an alignment? over here Toyota put GY integrity tires on them and they are terrible. crap tires, out of alignment, body flex, weak suspension all contribute to lousy high speed handling. front strut tower brace will probably help, but they are kind of expensive, and the cheaper ones look so flimsy I doubt they do much.

 

Would this be effective?

04 05 06 07 08 09 TOYOYA PRIUS FRONT UPPER ALUMINUM STRUT TOWER BAR BRACE | eBay

 

These are the best recommendations. Completely agree.

The biggest factor in the handling of the car is the tires' ability to make friction with the road. This is why the first upgrade is almost always tires. If you want better handling, go for a slightly wider (eg. 205/60R15) ultra high performance summer tire (easy reference is to use Tirerack.com and compare tires' ratings). Follow this with upgrading the sway bars.

Stability on uneven surfaces is mostly affected by the suspension. Worn out struts can cause excessive bouncing. With tuning the car for a race track or otherwise, too high of a spring rate won't keep the tires on the road well and grip will be reduced on uneven surfaces. Too low of a spring rate and the car's weight will shift too much in corners, causing slip on the outside tires and reducing maximum cornering speed. A balance for the conditions must be found for the car.

Also, a car in over-steer feels "unstable" to the average person. Research oversteer and understeer and their causes if you aren't already familiar.

 

the mounting brackets look kinda flimsy to me. they might be 1/4" thick high carbon steel, but for that price I doubt it. I have this one, which I got in trade for some diagnostic work for a priuschat member, so I don't know the brand, but the mounting brackets are very stout.

 

wandering could be incorrect toe-in adjustment; also snow tires aren't known for good dry handling. I don't know anything about nokia tires.
I set my tires at 40psi and never noticed a problem with wandering. I would want to inspect the suspension for anything worn and get the alignment checked first. then look into a quality strut tower brace.

 

Almost looks like a BT brace, except for the green brackets.

Do those brackets go full circle on top of the strut?

How is the access to the fluids and relays?

 

its raining now, or I'd go check to see, I think there are some rubber stops to keep the hatch from clunking. as much as I like these cars, they are kinda flimsy, so upgrading and adding braces is definitely a good idea.

 

I would go for the strut tower bar, because I suspect the strut towers are more likely to flex than the undercarriage, which already has a big steel subframe bolted to it.

 

I see you guys talking about the Corolla rear sway bar. Is there a specific year I should look for and can I use the front and rear bars from the same car?

 

Search the forums for exact years, but you'll want the front bar from a junkyard Corolla/Matrix. The rear sway bar on these cars is only slightly thicker than the stock Prius rear sway bar, so you'll want a 22-26mm rear aftermarket sway bar instead. Progress and TRD are popular models.

 

03- 08 definitely fit, but I think in fact the corolla bars are the same up to like '15. I got my front bar from ebay for $45. make sure you get the frame bushings and clamps with the bar too.

 

Thanks, that's exactly the info I was looking for.