they dont actualy flare it. a good exhaust shop should have a tool for putting a bead round the end of the pipe. they just roll it around and it makes sort of a raised edge. not too sure which metals they can use it on tho. definately ok for mild steel, i think alloy is softer(it is to drill into anyway) so i would expect it would work on that too.
the other trick is to have a small lump of weld onto the outside to make a raised edge.
you'll find in a front wheel drive the engine will twist backwards under load and if you dont have solid mounts or really good condition mounts it will probly sometimes pull the turbo loose out of the first joiner without a bead/lip
also with a small engine you want all the spool you can get, and having an absolutely sealed piping system helps a lot.
the proper full stainless t bolt clamps are the way to go too, as they evenly apply pressure right around the join. hose clamps and half clamps will either damag the joiners or not secure it all the way around allowing it to open under high pressures.