Yes. No. And no.
You can throw them on an otherwise 100% car and be good to go.
Now... if you also have an aftermarket cam and intake, you may want to look into upgrading to 24# injectors and a MAF tuned for them. With just the AFRs, you may also want to buy an AFPR and bump the PSI (or bars for our gay friends out there in TV land) up a little.
Also, the stock pistons thing is kinda dependent on the cam. With the stock cam, there will be absolutely no problem. With a mild aftermarket cam, there should also be no problem, but you'll want to check your piston to valve clearance to be sure. Every engine is built slightly different (factory tolerances aren't the greatest), so what clears on one may not on another.
Finally, a tune is always a good idea, but it is not necessary. My car has never been tuned, other than my own adjustments of fuel pressure and timing. With a good aftermarket mass air meter (i.e. Pro-M), the fuel mappings should be pretty damn close to what you will need. My car has over 25k miles on the motor now. I know it's running a little rich because the 30# injectors are a little big for my combo. But when I pulled the plugs last weekend, they all looked to be in pretty good shape. Well, except for the couple that you could tell there had been some oil in the combustion chamber, but that's another issue all together.
Basically what it comes down to is this: Buy 'em. I promise you won't regret. My AFRs are without question the best $1275 I ever spent.
