Hello to all

I have a 2007 FLSTSC  it came with a 150mm rear  tyre from factory, i would like to increase this to 200-250mm.  My previous 2000 Heritage invoved - Swing arm, Primary offset, Gearbox extension & 3/4 Belt.  This one looks different  as the Primary already looks ofset ?   So what changes have to take place to accomidate a 200mm tyre  or then a 250mm tyre ? 

Thanks