More speed with oversize tires

New here !
I have a 2005 Gem E4. Just bought. Put new shocks, tires(Dura Scorchers 22x11x12) & rims.
Raise back fender. Everything fits great. Ordered the R4F motor. No reprogramming controller per R4F for a 2005. Supposed to be able to get 35 plus. The shop that did everything said programming controller is a must, based on tire size. Motor a lone won’t get the speed. Is this true ? I like the look. But want the speed. There’s a lot of Gems with left kits and big tires.

Please advice. Thanks

Motor won’t add much speed. High voltage or taller gears, less money more speed.