> am i right in think A-188-1D with 4096 stages BBD is capable of

everything the rest are (those with less stages )

no, all the chips involve some measure of trade off and each has
certain benefits over the others depending on your needs (which is why
doepfer is offering so many options here). If you look at page 3 of
the a188's manual you will see the matrix of delay times that each
chip is capable of at various clock frequencies. The 4096's minimum
time (at its maximum clock frequency) is 8,19ms, which means that it
cannot do proper flanging (which ranges from < 1ms to +- 15ms).
Furthermore, the inverse relationship between the length of a delay
line and the frequency it is capable of producing in terms of
Karplus-Strong synthesis means that the 4096 will not be able to
produce anything other than lower pitches when employing this technique.

Also, its long pipeline means that its resolution at very short delay
times is quite coarse compared to the chips with fewer stages.
Looking at that table you will see how the delay time lengthens as you
decrease clock frequency and if you compare that with the 128 or 256
stage chip you will see how much bigger the steps are.

The obvious benefit to the 4096 stage chip, of course, is that you can
do regenerative delay without the clock noise interfering too badly.