I went to 35s on my 06 F150 4.6L. My speedometer is now off and am wondering which programmer out there works the best/ easiest to correct it? THanks.

 

Correcting for TS and GR is just a by-product of owning a programmer.

If this is all you're interested in, I would call a dealer or local shop and ask how much they charge.

If you're interested in performance gains as well as correcting your speedo, then I suggest you read the stickies and peruse this forum for tidbits of information.