08f150xlt

whats up guys, i used to be a member of "dodgetalk" but im a f150 owner now, so my question is, i heard its not ok to go with a bigger tire ex. 255 70 17 stock to 285 70 17 with a level kit. i was told all the electrical systems act up when you do this? speedo, 4x4 stuff ect. Is that b.s.? my truck is an 2008 f150 xlt, 5.4L supercab... would the dealership reprogram the speedo for larger tires if i bought them???? thanks guys