Debating tinting, should I tint the lower rear window?

It's not necessary. You won't miss anything.

 

I just had my 3G BP tinted with 30 including the rear window and excluding the windshield. The lower rear window visibility is still good and I like the look of the black spoiler and rear lower window 'melding' into one black unit. Are you sure 20 is legal or do you care? 30 seems plenty to me - YMMV!

I have a copy of the receipt stored with my insurance and title in the car in case I get pulled.

I also pulled the wheel covers and installed mudflaps and center caps. I like the look a lot.

 

The lower rear hatch glass is 29%, so it won't be exactly equivalent if you tint 20% all around (for an aggregate of ~15%, since the Prius is already tinted ~75% all around in the glass). It's also a different color (dark gray versus green in the other windows).

 

I didn't tint it on my 2005 I had and regretted it (had 20% all the way around). On my 2010 I have 15% and also tinted the lower rear window, I like it much better. Dramatically helps to cut down on headlight glare through the back windows at night.

 

Had the windows tinted in my 2008 and if the 2010 is like the 2008, you'll definitely want it tinted to match because of the color difference at least - went a shade lighter for it and came out pretty good - definitely better than without (it wasn't tinted initially).

 

i went 30 in the back, little windo included. you can only tell a difference from the inside. from the outside it all looks black. i would recommend tinting it, but wouldn't worry about making it a different shade.

 

I had my car tinted. At first I didn't have him tint the lower window since at night and in the shade it looks the same. However, in direct sunlight and an average sunny day, you can see through the little hatch. I don't know the exact % since I had him tint at "dark" but the visibility through the lower hatch didn't reduce at all.

Overall, I recommend it. But, it's up to you. Try it first without, then take a look at it in direct sunlight.

 

Had my Blizzard White tinted 20% on all windows but he front windshield. The tint shop said the bottom back window has tint from the factory and did not have to be tinted.

 

Yes, it will have an aggregate of ~15%.