I don't think LT's need much modification, if any, to be installed, as long as you get some specifically for your truck. and by your truck I think any 06-08 F-150's LT's would fit your truck. maybe even up to 2010 when they last had the older motors.
From what i have heard the shorty's don't do much except sound a little different.
If you do get LT's Bill can write you a tune for them, might get 20-30 hp from what I have heard... maybe more.
Hope that helped
