Would like better cornering.

First springs if you'd like a lower ride. If you have the budget, you might want to consider coilovers.

Wheels and tires would be next. 17 or 18 wheels with lower profile tires will help with turn in due to the shorter sidewall and stiffer tires.

Get a rear sway bar/brace. The car has a solid beam axle which connects both wheels. The rear sway or brace would help stiffen the rear.

I'd do a front strut tower brace. This will also help I'm prove turn in and steering response by eliminating/reducing strut tower flex.

There are some options for a front sway bar. They aren't Prius specific, but solutions which will fit the application perfectly.

Do chassis braces last if you are still unsatisfied.

Do each area until you are satisfied with how the car is for you. No need to go balls out and make it so stiff your kidneys are uncomfortable if you don't need to.

 

Peter pretty much covered it.

In my experience, 17" or larger wheels (with appropriate tires) make the single biggest difference in the ability to take corners faster. Lower springs are next followed by the various bars.

If you don't want to suffer the mpg hit of larger wheels then do the springs plus the bars. If that is not enough then add a set of wider 15x7" wheels with a +38 offset or go to a 16x7" wheel. The wider wheel with less offset enhances handling even with the same tire size and mpg won't suffer as bad as with a 17" wheel. Regardless, you'll need to bump tire pressure to 44psi or higher.

 

In order of mod based on your budget. 17" wheels, rear sway bar, springs, all the brace mods.

Our Prius have almost all the suspension mods now it handles very good. Even my wife who is not a car person felt the difference. And first time ever she actually thanked me for spending money on car mods.

 

I don't recall seeing anyone do this. Can you link to a thread in which someone did?

 

There wasn't a thread on the subject. It was something I observed when I was wheel and tire swapping like mad.

I thought about creating a thread but never got around to it.

 

More air in the Tyres would be the 1st and cheapest thing to try.

 

Honestly I don't know how that would make better handling? More air less rubber contact surface area, on race track we on purposely lower the air to get more traction.

 

Less sidewall deflection. In the case of the Prius, we are not worried so much about lateral grip as we are the immense body roll and tire sidewall rollover.

 

I purchased a 2013 about 1600 miles ago and asked the dealer to put Michelin primacy 17"MXM4 tires and rims.
We had to make a return trip several days later as the dealer needed to order the tires etc so we drove home (180 miles one way) on the 15's. With the 17's it is like glued to the road. The highway has lots of turns. As for mpg hit, yes but its not bad. I average 45-50mpg. The best was 52mpg.
IMO go the Michelin Primacy 17" MXM4 tires first. The easiest of the list you posted.

 

Rear swaybar is the best bang for your buck. Then 17" wheels. Then suspension/braces.

 

Do you have a Prius"c" or a Gen III liftback?

If you have a "c," look under the car, and you'll see that there are mounts for a mid-chassis under brace, but NONE has been installed.

I have again improved my billet aluminum brace. It now has a black epoxy oven baked finish. Check it out.

For Sale - My custom 2012-13 Prius c under chassis brace $67 | PriusChat

 

They pretty much covered it all. I did my wheels and tires first and it has made the biggest different in terms of handling. However if you like to take fast corners, body roll on the Prius is pretty bad. Despite the wider tire providing better grip and handling, the body roll doesn't inspire much confidence. Also, with the recommended tire size for the 17" wheel, tire and fender gap will be even worse than stock. It took me awhile to gather all the tools needed to do the springs upgrade, so my Prius had a wheel gap of a Crosstrek for 3 weeks. So be prepared, once you make one upgrade, you won't be able to stop Shop around a bit that link is a little pricey.

 

You could trade it in on a Plus Performance Prius, they handle very well and corner flat

Mike

 

wow, you can't get more expensive than your Prius from the dealer That's PIP + wheel and suspension money!!! My Prius doesn't corner flat, it just rolls less, I don't think you are going fast enough

 

The maximum recommended inflation on my OEM tires (Goodyear Assurance) on my 15" wheels is 44psi. Wouldn't bumping the pressure up higher than this result in uneven treadwear and perhaps even void the manufacturer's warranty?

 

In practice, no. The construction and narrowness of the tire precludes it from wearing prematurely in the middle like older and/or wider tire designs. I don't know any anyone that had center wear while running over the tire listed max on a Prius. I have experienced this effect back in 2002 with my truck tires, however.

The manufacturer cannot tell that you ran higher pressure unless you had center wear. You won't so you're safe.

That being said, unless you are seriously hypermiling and driving at lower speeds I wouldn't recommend going over 45psi on a 44psi rated tire. The mpg return on higher pressure peaks between 40psi and 45psi. After that, the mpg return starts to level off such that I feel the gain is not worth the harsh ride, reduced traction etc.. If you generally drive slow, drive on very smooth roads and like to hypermile then 48psi or even 50+psi is worth trying as long you understand the safety concerns.

 

No need to worry when inflating to 44 psi, maximum recommended pressure (cold pressure) is not blow out pressure, it is in fact many times that. Tread wear actually improves with higher pressure, along with handling (especially in the rain) Of course, all good things in moderation, we are talking about improving handling and such (you get higher mpg also ), you will experience reduced ride comfort with increase bumpiness and road noise at high pressure. Most of the tire problems actually happens when under inflated, and when you exceed the maximum load rating. Trial and error will help you find what is right for you.

 

I run 49 front 47 rear with MXM4 Michelin's. Awesome traction in the corners on the street.

Mike

 

I had it at 50/48, I didn't like the road noise and rattles from the highways around here. 40/38 was too soft, Now I have them at 45/43 and I think it is optimum for my taste.

WEOH - we have the same mpg, do you drive like me? Alternating between having fun and hypermiling according to mood. MPG differs from 30s to 70s

F8L - Do you feel that the PIP rides better? (stock PIP vs stock HB) I don't know if it was my imagination or not, the rental PIP I had felt smoother and faster. It felt like a much bigger car, but it is only a couple of hundred lbs heavier w/ 15" LRR tires. The dealer must have tricked it out to attract people from switching or maybe I was flooring the rental a little bit.