Welcome to quadraphonics and I urge you to do more reading. Enough so that you understand the various ways to go about assembling a quad system and how the different methods work.
That way, you will be able to decide how you want to go about getting quad in a meaningful way without confusion or at least the minimum amount of confusion :^)
Do a google search for quadraphonics and read all that is available on the main hits, especially how the different systems work - SQ, QS, CD-4, and tape.
Please take this as friendly advice. Quad is complicated enough that it really helps to have an understanding first.
We old quad guys had to go through this years ago and it is good.
Doug