Can anyone here tell me if other aftermarket exhausts can be used with the Mugen rear underbody spoiler or is the Mugen one the only choice?

I ask because I've picked up the Mugen front and grille so far but plan on doing the rear too. I'm interested in the Mugen exhaust but it seems pricey for what it is so I was wondering if other exhausts were an alternative.

Also, if anyone is running the Mugen exhaust I'd like to hear your take on it.

Thanks in advance for your replies.