Conveniently enough, all the tires needed replacement when I bought the car. Firestone itself recommended against using the stock tires, both due to issues of handing and durability. So, I bought:
Category: Performance
Segment: Touring H/V/Z Tires
Brand: Bridgestone
Model: Turanza W/Serenity
which has a 440 treadwear rating and a 50k mile wearout warranty. I didn't really drive it much with the worn-out stock tires for comparison, but I like the ones I have now.

 

I added a "Homelink" garage door opener to my HHR back in October, Got tired of the remote hanging down from the visor. Go to the "Forum Junp" then pick "Appearance Discussions" look for "Saturday Morning Mod"...I love the ease of use and, the look is factory....Also, Don't forget to look for some kind of prizm for your windshield so you don't have to bend down to look up at traffic lights.....Good Luck, Have fun.....Ohnomobile (Rick)

 

I am only 5 ft 5, and keep the seat all the way down. So, I can see traffic lights fine. I read about the prism/prizm thing, and it makes the car doable for people who either are tall or prefer the "commanding SUV seating position." I'm neither, but thanks for the suggestion.

 

I actually have all the modifications listed in my "signature" installed on the car now. I feel each addresses a specific need. Adding the suspension's absent rear sway bar (such a bar is stock on the SS) noticeably improved the ride. The factory horn is too soft and is single tone, so a louder dual-tone horn was a safety issue for me. The lower billet grille was needed to protect the AC condenser from road debris. The short shifter with weighted knob improves every shift a LOT (I kept running into the seat upholstery when shifting into 2nd gear with the stock shifter) and the knob feels better in my hand. The rear LED lights look classier and are more visible, plus 3 of my 4 stock lights' lenses were scratched up when I got the car (used, repossessed). I plan to upgrade to a 2009+ combo map light/sunroof control when they pull the headliner to do my sunroof repair. That should be about it.

I am not doing:
1. racing pedals - they look cool but are located where you can't see them while driving or from outside the car, and really don't add anything functionally.
2. cold air intake or cat-back exhaust. Expensive, minimal performance increase (if I wanted performance, I would have bought an SS but would have had to give up heated seats), and ADD NOISE.
3. stiffer engine/transmission mounts (ADD VIBRATION, really only useful for the SS).
4. stiffer or lowering springs. I love the politically correct "leveling" term, it's like saying gaming instead of gambling. I have a big driveway hill and don't want to lower the car. Also, adding the rear sway bar that is just plain GONE in the stock setup is a much bigger issue compared to modifying springs.
5. HID headlights. I believe these are appropriate only with a government-approved modification of the entire front lighting system. I remember when halogen came out, and that was a major improvement. The HID is incrementally better, but not as big a change as when halogens first arrived.
6. Any other appearance mod (I like how the car looks stock, other than the tail lights).

EDIT - I am doing one other appearance modification. I plan to substitute black for chrome center caps on my wheels. I already have three black ones, and am trying to get the 4th now to complete the set before changing them.

 

I added the HID lights glad I did CGS intake lowered almost 2 inches powered coated gloss black wheels Wet Okle seat covers black on black mImco T-910 mufflerupper and lower billit grills pinstripped not much more to do. have just purchased the Eibach Anti Roll Bar, as the TTR is no longer Avaible hope I will not be dissapointed.

 

The MacPherson strut independent front suspension uses SS-specific gas-charged twin-tube struts, unique steering knuckles with optimized geometry, 28 N/mm linear coil springs with specific damper tuning, stiffer control arm handling and stabilizer bar bushings, and a direct-acting, 23-mm solid stabilizer bar. At the rear, the SS's semi-trailing twist beam axle uses monotube gas-charged shocks with specific damper tuning, a 24-mm solid stabilizer bar, stiffer axle bushings and multi-rate coil springs (30-40 N/mm). StabiliTrak electronic stability control and traction control are standard.

http://www.motivemagazine.com/pub/ne...s_HHR_SS.shtml

The MacPherson strut independent front suspension uses SS-specific gas-charged twin-tube struts; unique steering knuckles with optimized geometry; 27 N/mm linear coil springs with specific damper tuning; stiffer control arm handling and stabilizer bar bushings; and a direct-acting, 24-mm solid stabilizer bar. At the rear, the SS’s semi-trailing twist beam axle uses monotube gas-charged shocks with specific damper tuning, a 24-mm solid stabilizer bar, stiffer axle bushings and multi-rate coil springs (28-40 N/mm). StabiliTrak electronic stability control and traction control are standard.

http://www.topspeed.com/cars/chevrol...53612-pa2.html

It looks like the 2nd source copied the front sway bar size wrong, multiple others use 23mm.

 

Yes all model HHR's come with the stabilizer (torsion) bar up in the rear axle.. Different stiffness FE1, FE3, & the SS has FE5

Why are so many SS owners adding rear Sway Bars ???

https://www.chevyhhr.net/forums/show...=14697&page=15

https://www.chevyhhr.net/forums/brakes-%7C-suspension-%7C-shocks-%7C-struts-24/sway-bar-29811/

 

Every HHR ever built has a rear sway bar. Some call it a stabilizer bar, anti-sway bar, etc. All the same thing. They add torsional resistance between sides on the same axel effecting roll and suspension balance.

All the non-SS cars have a 25 mm front and a 22 mm rear. The SS uses 23 mm front and 24 mm rear.

 

I have ordered the Eibach anti roll bar how do you like as mine will be here any minute just waiting for the UPS truck, thanks, Jay

 

Someone found a vendor for heated mirrors. Its primary product is actually signal mirrors, that is mirrors with embedded direction signal lights. The latter is something I'd never even considered. Details are on the heated mirror thread. This is one of the few things that might meet my criteria for modification, which is that it provides a functional improvement and doesn't make some other characteristic of the vehicle worse!