regardless of who OWNS the shop, you will have issues trying to pay a business to BREAK A FEDERAL LAW:
You can not modify the NUMBER, or the LOCATION of the catalytic convertor(s) on a vehicle, other than what it was originally manufactured with.
So, even if you were being a GOOD BOY, and did true duals, with 1 catalytic convertor on each pipe, keeping the NUMBER of cat's the same as your X was originally equipped with, you have modified the LOCATION of them.
And if you were to go the route that EVERYONE ELSE would do, and just delete the cats all together, you have modified the NUMBER of cat's....
Either way, you are breaking the law, and NO reputable business would do it...the main reason: EPA (who has jurisdiction on this)fines are in excess of $15,000/incident. And there have been well known 'stings' of 'plain clothes' officials taking a car in, and asking for exactly what you are asking for....they will do the work on the car, and immediatly fine the business $15,000!...it's been well documented that the EPA does not fool around with this stuff.
I am neither FOR or AGAINST the use of catalytic convertors on a modified vehicle.....but if you want to do what you are planning, don't count on a exhaust shop to do the work for you.
Ryan