Any warranty issues?

I just did a trip from SF to SLO a few weekends ago and had NO issues whatsoever w/ handling or anything, i was in a hurry driving there (80 mph but still 48mpg) and on the way home there was a BRUTAL headwind (had to acc downhill to maintain speed >40mpg) and the car handled perfectly

personally i don't think you need any of the "stiffening" plates or whatever, but its just my 2c

 

As well all know they cannot void any part of your warranty unless they can prove that your aftermarket device caused a failure.

That being said, I've never heard of a warranty being voided for simple upgrades like the ones you plan.

I concur with the wind vs Prius concerns though. It is just about the only gripe I have with this car. I've driven in some pretty nasty conditions and nothing bothers me more than the wind issues. Even with the BT plate I still do the freeway wander.

 

What is it you are specifically looking to improve? Comfort, handling, or both?

 

I have not personally driven a Prius with the modifications you suggested, however i have driven many other vehicles with many types of modifications and un my experience stiffening a vehicles chassis usually results in a somewhat harsher ride quality. Since the vehicle is going to be utilized for longer trips this may be an issue. Perhaps some of the folks who have actually made these modifications will be speak up about their own actual experience.

My one gripe about the Prius in regards to comfort is the seat. Seats are entirely personal based not only on body type but also preferred driving position. My wife likes a straight up seat back and soft seat. I like a very laid back position with support under my knees. Seats can always be modified if you have the inclination, time and energy to do so and a comfortable seat can often ease any stiffer suspension issues.

One little thing I use is a suicide knob. In some states these are illegal and I always mount mine pointing at the four position on a clock face so it is rarely sticking up where my forehead might hit it, but I have found it to be very useful on long trips from the perspective of changing my grip positions on the steering wheel and maintaining a firm grasp at the same time, and it is especially convenienet in parking lots. If you try one I suggest something round and heavy, not lightweight and "cool". I have an eightball design that works just fine for me.

As far as warranty... As others have pointed out, unless a failure results from an aftermarket component then your warranty coverage is not affected.

 

I drive about 140 miles a day, all on the high way with speeds at 65mph. The car has no wind resistance, so i am constantly struggling to keep it going in a straight line. I put on bigger rims, and some really good tires, which has helped a great amount.

 

I thought I was pretty knowledgable and "with it", but I guess not.. What the hell is a suicide knob?