Good afternoon everyone.

I'm in the midst of reshelling my vrs into my sdi and decided to swap the firewalls over, as the vrs one has the hole for Aircon and I'm intent on swapping EVERYTHING over. 

It's held in by 6-7 13mm bolts which I have removed, however it's also held in with some of the strongest seam sealer I've seen.

I've tried heat, which didn't do much. Used cutting wheels which just destroyed them and made enough smoke that I'm glad there isn't a smoke detector in the shed. Used a Stanley knife to try cut away at it bit by bit which did nothing but destroy the blades. And even went so far as to try wedge a chisel in between the firewall and the chassis which only served to break the chisel.

Surely someone's encountered something like this before and can give me some help?

All else fails I'll drill the required hole in this firewall and do it that way.

Thanks.

Given what you've said I'd be drilling the hole in the sdi firewall... 

Same here, sounds like much less grief.

I shall get the sawzall then.

And some tigerseal to fill what I've already cut.