First the question then the story...
My tire blew and I Just bought a new left rear tire for $400
The right rear is still original but I just compared the tread depth to the new tire and it's got about half the tread...
Finally the question... What does a person do with the tread difference?
Live with it?
eat another $400 and buy a right tire to match?

Shave the new tire to match the old?
Find a used old to match the right?
Below is the entire story of what happened... sorry it's long but I like to write

. If you don't wanna read it then skip it and if you can give me a suggestion to the above question, I can really really use any suggestions.
Thanks.
Now the story...
I woke up early to meet a buddy at the gym for a workout. The weather was good and I haven't driven the car much since I became a daddy recently and thought I'd take the Z.
About 2-3 miles out, I'm about to turn off from 441 to palmetto and can't wait to hammer it cause the Z should be warmed up by now and all of a sudden I hear a major "POP!" and tinking sound!
In denial, I thought for a moment that it was the clunker in the next lane making that god-aweful sound. I turn off into the other road and realize from the tinking sound that followed me thru the turn that the god-awful sound is coming from the Z!
On that intersection I just turned off on is a Walmart so I turned into their parking lot, immediately got out of my car and, already fearing the worse, look at my rear tire and it is completely flat! Words cannot describe the feeling so...
This is my second flat in the Z. The first was a construction nail also in the rear that I ended up getting patched but I was luckier then because I spotted it in my garage and it was a slow leak and I could drive it to a tire store. This one was as flat as a pancake.
I couldn't immediately see the nail so out comes the tire kit that came with the car. I followed the instructions... pretty simple... poured the gunk into the tire and then plugged in the compressor and let her blow. After a minute or so... nothing. So I take a more detailed look at the tire... and it find an aluminum tubed piece of shrapnel (sp?) sticking out of the center of the tire! At least I know the tinking sound was from the metal shrapnel hitting the road. I put my hand over it and can feel warm air being pushed out like a hair dryer from the compressor! Nothing was gonna plug up this hole... even a runflat couldnt have survived that! This really sucks now cause I'm worried I have to have this car towed.
Luckily it only happened a few miles away so I called the wife, in-laws watched the baby as she picked me up and drive me home. I picked up my heavy duty floor jack, 2x6 wood and drove back out in my wifes Lex to the Walmart parking lot. Fortunately being a Walmart, I went in while waiting for my wife and bought 2 3-ton jack stands and a lug wrench.
I placed the 2x6 under the rear crossmember, jacked the car, lowered it unto the jack stands and removed the rear wheel.
I tried one tire shop and no suprise they didn't carry the F1 tire.
Luckily Lou Bachrodt down the street was still open so I drive there and they have the tire. They cleaned the gunk, mounted and balanced the tire and I'm out in about an hour and out almost $500 bucks ($400 for th tire, the rest to mount and balance)! I didn't know exactly how much it would cost... didn't care considering the cirsumstances but when I actually heard... words cannot describe the feeling so....

!
I drive back to the Walmart to find my QSZ parked in their lot with the rear on jack stands and missing a rear tire (it really was an interesting site), mounted the tire and drove it home where I come and post my story here to find out what I should do with the difference now in the rear tread depth.
Well, if you made it all the way to the end, hope you found it interesting and maybe it'll make you think about and dread the day this may happen to you and maybe you can do something to prepare in case of such a scenario.
I don't think there is a moral to this story except...
"times like these I'd forego the wait savings and wish they had a tiny spare?"
or... "is there a tiny spare that will work with the Zs that I can toss in the back with a little mini jack?"
or... "have a spare set of tires at home in case of emergency?"
$400 bucks!
Don