Since you have an 03 the bungs should be in the right place for you. On the 04's the bungs were in a different spot on the OEM pipe, so you had to use extensions to get it to work with aftermarket pipes.
Also, check with your local emissions testing procedures (if you have emissions testing) before "turning off" the rear O2's. In some places you can do that but in others the testing machin looks for a "ready" signal from those sensors. If you are the later and they are "turned off" then you will fail the test. MIL's are the common solution to resolve that problem.