Horseface,
Congratulations on the garage system. Nice story on how it started. When I think about it, I feel - why not? A garage is bigger than the average room and the system will sing fantastically if you optimize the speaker positions and use some treatments. You have a nice start. Who cares about how much a equipment costs, as long as you are happy with it and it gives you the result that you are looking for. Keep experimenting and try to achieve what you must.
Above all - enjoy your music!!