Front ride height

Did you have it aligned after you did the front end work? Mine is a little twitchy, and I think it's probably an alignment issue.

If you put larger tires & wheels on, you may have clearance problems in the wheel wells. Also, it will mess up your speedometer and probably lower fuel economy. If you lower it by cutting the springs, they probably won't fit in the struts--but even if they do, you'll mess up the ground clearance. I'd probably take it to an alignment shop and ask them what can be done to tighten up the steering effort.

 

Mine was still running all four factory struts at about 15.5 years and 209,000 miles (336,000 km), and the steering was starting to feel a little weird. The main place I noticed it was on long, sweeping curves on the Interstate (motorway), at 65+ mph (105+ km/h)... it would kind of understeer (head for the outside of the curve), and trying to gently correct that with the steering wheel didn't do much for the first little bit of steering wheel motion... then it would suddenly have an effect. New struts all the way around (at the shop) improved that situation a lot.

You probably did this already, but make sure you have the air pressure set how you like it on the tires. I don't remember the factory spec but I know it's about 2 psi higher in the front. I run mine at 42 psi front, 40 psi rear (tires are rated 44 psi max). I have given up on having any shop set the tire pressures correctly on any car after any tire-related service; I always plan on spending a little quality time with a gauge and a compressor after I get it back from the shop.

If your tires are about evenly worn front and back, then this might not help, but otherwise, you might try switching them front-to-back to see if that changes the feel. If it does, maybe some new tires would help. The ones with better tread are supposed to always be on the back, but as long as they aren't totally bald, driving it a few miles the other way around as a test is probably OK. Also, it's something you can do in the driveway at home.

I just measured mine - the left and right sides are a bit different, but the average is 369 mm (14.53 inches). This is with the nose very slightly downhill, and when I parked it, I put on the park brake first and then shifted to Park. In other words, it's "sitting" on the park brake, and not on the park pawl in the transmission.

 

I did a set of struts on a second gen Prius this summer. The shock portions were completely shot--still looked like new, but absolutely no damping action. I suspect that this could influence the steering feel, certainly made the car lean a lot going around curves.

My 02 is due for a steering (tie rod ends, ball joints, control arms) rebuild and new strut assemblies. @ 203,000 miles, it's probably due. I'm waiting out the weather, 105 here today, a bit warm, but supposed to get down in the 80's by the end of the week. Wrasling with suspension components in the heat is not my cup o tea. Symptoms for my Prius is wallowing in curves and it bottoms out on speed bumps. I'm looking forward to it handling a bit better, while I've got the rear seat out, I'll install a Prolong wiring harness.

 

You dropped the front and raised the rear, did you mention that during alignment.

My ram eco diesel has air suspension and goes up and down 5”, watching the front wheels from the front is interesting as they....going from down to all the way up move to be in alignment with the ride height, biggly....

So, the alignment specs change radically as you go up or down, especially in opposite directions from stock.

Anyway, now pump the tires up to 42-40 and put on new struts to replace the six year old suckers.

 

36 PSI is sufficient. Any more and the ride gets pretty harsh. One of my tires/fancy wheels has a slow leak. It was down to where it wouldn't register on my fancy trucker's air checker gauge. Everything is now 36, my pickup, too. Hope my mileage gets better, 31 mpg is just ridiculous!

Between car batteries and parts to prepare an engine for my truck, I feel your pain. I THINK our little cars are pretty much worth almost anything we have to do to them to keep 'em alive. At least here in the desert, where rust just doesn't happen. I'll show you all when I get going on the steering and suspension overhaul. Stuff looks like it just left the factory.

As for parts, I think I'd check out Rockauto Canada. Check the prices, the exchange rate, shipping, and import duties. Might be cheaper than buying in the UK. I probably wouldn't import directly from the US, as who knows what the trade war has done to the import duties.

 

I know this sort of comment tends to create much friction about specific cars and their longevity....but I have oft wondered if Toyota did far more hand finishing on the Gen1 Prius than the Gen2 and beyond. Mine is now 17 years old and like yours lives here in the damp UK with our shitty roads, yet it drives really well, feels solid and is pretty much rattle free. And it certainly hasn't been resting in a garage for it's entire life.

 

I don't know if they hand-finished the Gen1 - I'm not sure it would have been possible at their production volume. I do have an idea that Toyota wanted the car to succeed based solely on the hybrid drivetrain, so they spent a little more money on the body, suspension, interior, etc, to reduce the chance that those would be the source of problems. I don't have any support or proof for this idea, though.

If people ended up thinking "wow, those hybrids get good gas mileage, but the doors rust out and the suspension is loose", that would have been bad for sales for the next several years. One of the big reasons we don't have passenger diesels in the US is EPA and CARB, but the other big one is the GM 350 diesel of the early 1980s, which taught most US customers to run far away from a diesel anything. Also, Toyota tried to sell the Toyopet in the US in the 1950s, and it flopped - I think they learned pretty well from that how to not have a new car flop.

Another piece of information is that all the NHW11s (2001-2003 model years) were built at Motomachi, which is Toyota's second-oldest plant (1959). If your QA is really good, it's not supposed to matter, but I think sometimes it helps if you get the people who have built a few cars before to build your new model.