I had a '96 Montessa. There isnt much difference to the bikes from around the '90s compared to now, apart from the weight, which isnt much, and a bit of power.
We have a VCR of the '91 world champs with Dougie Lampkin and Mark Colemner, and they were still doing insane things.
This whole video is good, but watch the part at 4.20min