Sorry to come off harsh with the search. Alot of people don't do it at all and we have a million threads covering the same topic. Anyhow, when I say trust me, I mean that depending on how you use your vehicle, you will save time and money by doing a lift right the first time. At first, i had a 2.5" spacer. It clunked bad (UCA contact with spring) and the ride was stiff with no real advantage other than looks. Then i went with the 5100's. For most people, these are fine. Combined with aftermarket UCA's I imagine they are great (Ask Derek24). However, the did not dampen the big bumps to the extent that I desired. I finally went with aftermarket (ICON) C/O's with Camburg UCA and wow, it is the real deal. Really makes your vehicl capable. If you are never really offroad, stick with spacers (clunking comes from bumpy ground). If your occasionally offroad with moderate expectations from your tundra, go with 5100's. If your really wanting to get after it offroad, C/O's.