Sorry for the confusion - I've spent a huge amount of time in the past year reading their various pages as well as many here and it is very easy to lapse into 'insider' jargon. Febi-Bilstein and Bilstein are different brands within the same German entity that do subsets of different bits we need for the suspension jobs. I suspect you'd need to go to the "about" page, but from what I remember Fe-Bi is the abbreviation of the founder's names in a very German manner of what they refer to as "silbenkurzwoerter" - syllable abbreviations : taking pairs of letters out of constituent words and then making a not-quite-acronym out of them - probably the best known in English is NAtional soZIalismus" - national socialism political movement / NaZi, and so on. Ferdinand Bilstein was the founder - from whom FeBi is derived. Bilstein are their well known suspension brand who make springs and shock absorbers, much as do Sachs and other companies like that. The Febi brand make pretty well everything else from drop links, to nuts and bolts and washers, to fuel filler caps, all sorts of engine sensors, to rubber bits in suspension etc.
In a nutshell - don't worry about it. Get Bilstein B4 shocks using Damadgeruk's link because it is the best price by far for a really good middle of the road oem-grade shock for our A2s and the difference in price will pay for a bunch of other components you need such as the drop links and ARB bushes etc. - and other bits as you have planned. Meyle HD are just as good, as are Lemforder for some of these. If the springs need replacing, go for whatever you believe suitable. I used Monroe SP3248s from a recommendation here along with B4s and they have proven fine for my Tdi (just done another 550 mile each way drive this last week along the country and they were great again) - firm/absorbent over Dartmoor and Scottish highland roads but not harsh (this is with 16" SE wheels, 195/55/16 Uniroyal RainSport3 tyres from Camskill) so there is plenty of sidewall and suspension travel to cope with ruts etc.
Hope this helps. Good luck!
In a nutshell - don't worry about it. Get Bilstein B4 shocks using Damadgeruk's link because it is the best price by far for a really good middle of the road oem-grade shock for our A2s and the difference in price will pay for a bunch of other components you need such as the drop links and ARB bushes etc. - and other bits as you have planned. Meyle HD are just as good, as are Lemforder for some of these. If the springs need replacing, go for whatever you believe suitable. I used Monroe SP3248s from a recommendation here along with B4s and they have proven fine for my Tdi (just done another 550 mile each way drive this last week along the country and they were great again) - firm/absorbent over Dartmoor and Scottish highland roads but not harsh (this is with 16" SE wheels, 195/55/16 Uniroyal RainSport3 tyres from Camskill) so there is plenty of sidewall and suspension travel to cope with ruts etc.
Hope this helps. Good luck!