Which suspension would an 05 LS have? Need to know since i have to buy a new outer tie rod. Thanks in advance

 

Suspension packages were optional. You can see which one is in your car by looking at the spare tire cover. There should be a label with all the options on the vehicle(your vin will be on it too)
You are looking for an option like FE1, FE2, FE3, FE4

There is a nice selection here
2005 Chevrolet Impala Tie Rod End - First Equipment Quality, Mevotech, Moog - TheAutoPartsShop - TheAutoPartsShop
You can narrow your choices by selecting a brand