Timing question and new exhaust
 

This last weekend I replaced the drivers side front fender that was damaged in a fender bender. While I had the left side of the truck wide open I decided to get a close look at my fuel pump.

Well I thought my truck was bone stock but it looks like my timing has been advanced. I am not sure if anyone can tell by the picture if it has been advanced. Is this something a normal shop would perform or most likely the previous owner? The thing is that the guy i bought the truck from who was the original owner doesn't strike me as someone who would modify the truck. I also took a look at the fuel screw cap and it looks as though it had been pried off once before. I don't think it has been turned in very much if at all because I really have to give it the business to get any smoke and it's a light haze at best.
Attachment 67611

This is a side note. I was going to install a new turbo back from Diamond Eye but a few things came up that forced me to improvise. I had the exhaust cut right at the muffler(true shorty) but the noise was getting to me. I had save the tailpipe off my old '07 and with a little welding help from the guy at work a 'hacked-up" shorty was born. All i need to do now is build a 4" down-pipe. There is a factory resonator that really seems to cut the noise back or maybe it's the fact it is dumping out the side of the truck and not right in the middle. I do get a nice deep tone.
Attachment 67612
Attachment 67613

Using my fine-tuned eye-ometer, I'd say that was a standard 1/8" timing bump. [laugh] While it can be considered a performance mod, if the PO was a pretty straight kind if guy like you said, I'd say it was done more for mpg's than go-fast.
Still, that's all speculation on my part! [duhhh]

I kind of figured it was for better fuel mileage. Will advancing the timing shorten the life of my transmission? Does it add horsepower? I need this truck to last for a while while I save for "better" parts.

it will not shorten the life of anything, just increase top end power and increase MPG's.