My first question would be why are you installing 2 inch tail pipes? Seems like you arechoking the system off. Unless you are a closet Tuner? And this is on your civic.
1) As suggested above, rent a pipe expander and expand the pipe and use exhaust clamps
2) Use a 2" diameter band clamp. It's basically a metal band that wraps around both pieces and has two bolts that clamp it shut. It's about $10 and may have to be specially ordered. Summit carries them as does some auto parts stores. I got one at O'Reilly.
3) Take it to an exhaust shop and have it welded. This method provides the most leak-free assurance, but it's obviously welded, so it would have to be cut to remove the exhaust if you so desire.
Glad you cleared that up I was starting to wonder about you. I like the weld method specially if they are stainless so you can take em off and use it on another vehicle down the road. Or re use it when the rest of the tail pipe rusts out.
maby like $10 bucks...it's a 2 min job....inluuding setting up the bender/expander. We have guys come in all the time and ask for something expanded or shrunk down.....or bent. Hell we have guys bend 1/2" copper piping and want us to make a complete exhaust system using the 1/2" pipe as a template