Found interesting DIY Scanspeak/Vifa speaker website!

Does anyone know of or have heard of speaker kits from the following Dutch based DIY speaker website
There kits are freely published including cabinet drawings and crossover constructions. Their kits mainly consist of Scanspeak and Vifa drivers.But there are no specs or description of how they perform! Could not find any info or reviews on the internet on these DIY kits.
If anyone out there knows of any reviews of the following 3 kits from that Dutch website, please let me know what the quality of these kits are and how they compare to other DIY speakers like on Troels Gravesons website or the Eros project by Wayne Jeaeske.
1.Scanspeak Reference Plus
2.Scanspeak Ultima
3.Vifa premium 33

From Australia you are better off buying drivers and making up an xo based on an existing xo design. Wes Components have great prices on Vifa, Peerless and Scan Speak.

I can pretty much tell you what kind of specs you can expect from typical midbass drivers, most aren't that much different. A small TM vented bookshelf with a 6.5" midbass should get down as low as 40 Hz and put out about 85 db with 1w @ 1m. A floorstander version will have about 6db more output, 3db more efficient and have 3db more due to increased powerhandling. Hence it will be about 88db efficient.

Put either of them in a sealed box with a Q of 0.707 and you get an F3 @ 80 Hz.

Put them in a decent TL box and you can easily get down to below 25 Hz in room in a typical Australian living room.

There aren't many kits in Australia, but one source is

Sourcing the parts yourself can be cheaper and give you more choices.