If they're not the originally-specified speakers you, like any pioneer, can expect some arrows in your back; or maybe you'll discover sonic paradise. These small systems are manufactured as a set for a reason. If anything has proprietary connectors I'd avoid modifying them for use with unmatched components.
There's a lot more going on in a given speaker than its impedance.
Answers & Comments
If they're not the originally-specified speakers you, like any pioneer, can expect some arrows in your back; or maybe you'll discover sonic paradise. These small systems are manufactured as a set for a reason. If anything has proprietary connectors I'd avoid modifying them for use with unmatched components.
There's a lot more going on in a given speaker than its impedance.