[RICK LAKE]

Brent I have used both. You need to be sure that neither one will effect the O2 sensor readings. How much pipe do you have that goes into the header pipes and slides into? Other question is about support of the mufflers and keeping them moving with the motor and not the frame of the car.
I know there is not alot of room, band clamps may also fit and seal.
K&D sell a tail pipe kit with either and expander for inside the tube or reverse cone tool to squeeze the end of the pipe, keep round and take up the room.
I have the origninal pipes and mufflers from ERA of 16 years and have used both antiseize and let the motor warm a idle a couple of times. The other times at the track have been with the RTV orange hi temp. This needs clean areas and a couple of heat cycles to cure. No back pressure on either until heat cycled or you will blow it out. Both are about the same to pull apart if needed. Resize the header tubes and red rtv will work fine.
1 side note, does your motor have a PCV valve? If yes make sure you are not having alot of blow by for this will richen up and cause lean out. Fresh air does the same for the other way. Rick L.