Exhaust Shopping

Okay, Im getting a new exhaust system put in, with 2.5 pipes and flowmasters super 40s. Im looking for exhaust tips. Now, Im ordering the tips online and just want to make sure, the outlet size of the tip does not matter but Im thinking the inlet size would. they have 2.5 and 3.0 " inlet size. Now I just want to clarify this up before I order, since Im getting the 2.5 pipes installed the size of the inlet size for the tips would have to be 2.5 right? Im thinking yes but just wanna make sure. thanks!