look at the peerless audio website
the 3.5 inch full ranger - pick one with 90 sensitivity so its easy to drive with a cheap chip amp
stick that is a ported cabinet
im sure there are couple helpful guys on the forum who will recommend the cab specs
provided you give them the TS parameters of the driver
use of 12mm MDF is sufficient
no bracing reqd for a 3.5 incher
since theres no crossover the build is really simple
just connect the driver to the speaker terminals and stick the driver in a cabinet and your done
cabinet is as simple as this
http://madisound.com/pdf/markaudio-enclosure-plans/CHP70-BR.pdf
just change the dimesnions as adviced according to the TS parameters
youre not gonna have heavy bass - but a nice smooth midrange with a non fatiguing top end
cant expect too much for 4 k can you