Mine is 2-1/4" as 2-1/2" is kind of big until you are looking at like 140 hp. Also if you are thiking of the factory LX 5.0 tail, that is a 2-1/4" pipe too although it would pose no more restriction at the end of a 2-1/2" system.
I agree you should find a long tube header. It's too hard and costly to find a Ranger header for its improvement, I got one because I wanted to see what kind of a difference it was and it sure pissed me off that I could have just gotten something else instead of seeking this legendary peice. Also you will have great difficulty getting the downpipe JUST RIGHT so that it misses the firewall and transmission and comes out at the correct level and angle. Starting off with a long tube will simplify the job to the point of one catalytic converter and a pipe with an S-bend to offset it to line up with the catback.
I agree you should find a long tube header. It's too hard and costly to find a Ranger header for its improvement, I got one because I wanted to see what kind of a difference it was and it sure pissed me off that I could have just gotten something else instead of seeking this legendary peice. Also you will have great difficulty getting the downpipe JUST RIGHT so that it misses the firewall and transmission and comes out at the correct level and angle. Starting off with a long tube will simplify the job to the point of one catalytic converter and a pipe with an S-bend to offset it to line up with the catback.