IMHO I would recco just touching up any paint chip/scratch or rust areas - if any - on the front wall (mainly for rust prevention purposes - not looks), & then use a good quality automotive interior/carpet adhesive or construction grade exterior rated adhesive for remounting the new mouse fuzz carpet piece on the front wall.
Same thing with the carpet on the floorboard - use the adhesive on the topside & big staples on the underside - just like the factory did it, unless you got a kit with the new carpet already attached toa new floorboard .... then it's ready to go.
There really is no reason to add a mounting board, nor drill for snaps (possible rust spots there in the future), & the velcro has adhesive on 2 sides which gets gummy in heat & over time & peel off.
So why not do it the same way the factory did it??
Nobody wants to see your backside anyway!
.... of the trunk wall, that is!
If you really want to dress-up the trunks, then get an interior & 2 trunks floor mat set from one of the Lloyds suppliers, & have them all embroidered with the PORSCHE logo & your 914 model number in some color(s) to your liking that match the car paint or whatever you like (upcharge when you order them).
If you prefer the period correct Coco Mat look inside, then just get the trunk floor mats in either coco, plush or other. CocoMats.com has the best selection, fit & quality IMHO.
They're all available in a couple of plush types, &r Berber in several colors close to the OEM carpet selections - & the Coco Mats same thing, plus a couple of other woven mat materials from some suppliers (e.g.: Sisal, Palm fiber, etc.).
Cheers!
Tom
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