Yeah they will bolt up to the cat no problems.

Never had an issue with my Dreamscience other than the clutch started to slip. Some do some don't so I upgraded to an RS clutch.
Only issue I had with the Dreamscience was i couldn't put it back to standard map so lost a couple of hundred quid as I couldn't sell it on then. Probably something simple but didn't have time to sort it before selling the car.

Other than that never had problems with the DS maps on my car.