#1
i've been thinking about building some effector clones. Will i get any better result using audio capacitors like musicap, jenson, MIT and WIMA?
tired of finger speed exercise and turned into slow blues improvisation lately
#2
You'd really have to test for yourself, although, very old designs probably originated with cheap ceramics or paper oil caps. Generally speaking a poly film cap will do the job of coupling caps sufficiently well. You can typically find them for under 50 cents a piece. Silver mica can be used for anything under one nanoFarad but will probably cost a little more than a typical film cap, although it'll have a tighter tolerance (more precise component). There is often debates about capacitor types and that "magic" tone, most of it is complete crap. The main focus is coupling caps, since the signal must completely flow through them.

Here's something to help get you a little familiar with the types.
http://www.radio-electronics.com/info/data/capacitor/capacitor_types.php