5 7 08 silverado drop

Ok so i have a 2008 silverado with 24's on it.I love the look of lowered trucks and i wanna lower mine alot. I have the money for a drop but im new to this so i need some help. What would be a good kit for around 800 bucks? and would i have to notch it? Also what tires should i run cause i dont wanna rub horribly. Im running 305/35/24 right now. Any help would be appreciated.  

I have a buddy that has a newer body chevy and his is dropped 4-7 on the stocks. It isnt notched but he says it does bottom out if a few people are in the truck, but helper bags would help out with that and u would still be able to tow things and put stuff in the back of your truck. Im 99%,sure those 305s are too wide, i had my 07 classic dropped 4/6 on 22s and i had to run a 265/35 r22