Running without Catalytic converter heat insulator

2007 Base Gen2 Prius

My prius' Catalytic converter was stolen.. again.
Classic.

I am attempting to install an aftermarket cat myself, but the heat shield/insulator was damaged in the theft.

I would love to replace everything, but am trying to spend as little as possible on the repair and the OEM Heat insulator (Toyota 58151-12220) is pricey, costs about as much as the cat kit.

I've looked around on the internet but haven't found much information on people's experience running the car without the insulator.

I was hoping to get some insight from someone with a bit more mechanical experience on just how bad of an idea this would be.

My other options would be to somehow hobble together the part, or use some other heat insulating material to bodge a solution.

Appreciate any info or shared experiences.

Thank you ahead of time.