X2 with what
@wsteele said.
I always wanna say the updated rocker cover was mid-2010, but that might be inaccurate. Not sure about the updated VLOM.
125K is very good mileage, especially for an '07. First order of business is to see if there are any documents pertaining to the maintenance- dealer service or recall or TSB work performed, etc. This would help to verify the mileage and history. Look for leaks, etc., just as you would with any used car. Next, listen to it with a cold start, if possible. Have someone start it while you listen for lifter ticking. An exhaust leak from broken manifold bolt(s) is really common and sounds like a lifter tick. But, the ticking from a drained lifter at startup usually subsides quickly as soon as oil pressure builds. Speaking of, watch the oil pressure gauge after startup. Infrequent oil changes, and, even worse, with crap oil, is the main killer of the AFM system. Look under the cap for buildup, check the dipstick, see if it has an oil filter from a quick lube place, etc. Listen for other sounds as it warms up and as you hold the brake and shift into each gear. On the drive, keep the radio off and A/C blower turned down so you can listen for other noises.
If it checks out and he gets it, he should pop off a rocker cover to see how the insides of the engine look. This will indicate the maintenance and care it received and what, if any de-sludging measures need to take place. I'd recommend disabling AFM to kick that can further down the road. It can be done for about $60. He'll never see the miniscule MPG loss, if any. Even better, if he has the cash, get a full tune by a reputable and competent tuner. This will disable AFM, improve response and drivability and help to prolong the trans life if the tuner honestly knows what they're doing. A Blackbear tune would ensure this, but you might know of a local tuner that can do just as well.
There are a ton of smaller items that are common issues or complaints, but those can be easily remedied after purchase.
