http://www.lmperformance.com/53569/119.html
You can put them on yourself.
I think it's been shown that there is no HP increase. However, the mufflers weigh like 24lbs each. So you 'll probably shed an easy 30lbs by taking off the OEM mufflers and putting these on.
BTW: Take a look at Borla as well. Just a little more but I like the way the tips are already welded on the mufflers. One less thing to put on. Just a personal choice.
http://www.lmperformance.com/53588/119.html