They should all be the same part#. The DME relies on both the signal strength, and the comparitive strength of the other sensors to do it's job. It doesn't take too much variance to make it act screwy.
You could be OK, but if not, you'll have a poorly performing car and will have to do it all again.
It's usally cheaper to do the job right, then to compromise and have to do it all over again.
