Frankenlift is amazing. I love mine. Two years ago I didn't know the difference between a shock, strut, or spring and was able to install my Frankenlift with the help of a friend (took an entire afternoon). We could definitely do a lift part sometime...
Another good lift to consider is Rusty's coil lift. Not quite as much lift as the Frankenlift, but has great ride and enough lift to fit 245/75/16 tires.
Do you need shocks? Yes, with a 2.5" lift you would be topping out the stock shocks all the time.
Do you need new tires? No, but you will WANT them! That's something you can put off until funds permit (just ask TokyoJoe).