madarcher 427

I have a nova that iam thinking about turning into a tactical gun,where & how much do the tactical barrels cost ? second the field barrel I would like to have the forcing cone lengthened & polished for optimal pattern what does this procedure normally run ? I am considering getting the vinci or m2 hwo well the pattern & what combo you used ? what is the differce between the vinci & m2 they both feel good in hand