£489 for the pair is alright considering what old electric recaro's go for! you'd have to add the cost of subframes to that though.
you don't need to cut anything out of your mk2, just undo the bolt at the front and slide them out the back. the new seats should have a subframe available which should sit in the original fixings.
to be honest conker, i know a guy who has mk4 recaro's in his car and while they look great, they are too wide and sit too high... in my opinion. a decent second hand set seems to vary alot in price and its not the simplest seat to fit. mk3 recaro's are sweet and need only minor alterations, but still seem to fetch good money for a decent set.