Yes you can tune these 05's...Mine is a 05!
As for the high mileage check the records and see if it has had any issues. It seems that some have a lot of issues while others have none...I guess it matters what day it was built on...lol.
I'd also take a look at the trans cooler lines as it appears that they are leaking in this pic you posted...It's a very common problem, so no worries there...just check them.
Let us know if you get her!