Absolutely! I had a fifth 18" Monza nicely tucked in the back with these inserts and it really keeps the boot clear of all the usual cruft you might want to keep in there.
Three things I found when doing this though:
1) The inserts I sourced needed a slight trim in the connecting 'jigsaw' tab as they just were that bit too big to easily fit (simple to do with a stanley knife)
2) In case it wasn't obvious the inserts will raise the height of the boot floor by not an insignificant amount and as such reduce boot capacity. Be warned if you do an ikea run or go on your family hols and your luggage only just fits.
3) The stock Mk5 GTI carpet doesn't have any support beyond the centre where the space saver wheel is. This means that if you put anything even slightly heavy in the boot to the left or right of the wheel (shopping, small animals etc) then it will just push the carpet into the insert cavity.
As a temporary measure I used some corrugated surface protection sheeting to reinforce the carpet - it can be easily cut to size, nicely rolls up in one direction when you need to lift the carpet and keeps things mostly out of the inserts. The "right" solution is to source the carpet from an R32 which had a full sized spare as this comes with the fully reinforced backing to the carpet. You can also identify the carpet for a full size spare by it having a 'fold' near the handle (in case you're looking a t a load of ebay pics and they don't show the underside). Part number I believe is 5K6863463A1BS
Thanks for this information!
The foam parts look almost impossible to find for a decent price, so I might go down a different route.
Would it be possible for you to measure the depth of the wheel well on your car up to the top of the foam inserts for me? I'm thinking I shall buy a couple of those thick insulation panels and just cut the wheel well shape out and have that underneath the carpet rather than having my pockets emptied trying to find genuine VAG versions.
