Hi. As it is now, you haven't provided us with enough information to make a judgement.
First of all, when you say you built a receiver, do you mean you made it yourself?
Whatever the case, you need some more information about the receiver.
If it puts 100 watts out at 8 ohms, how many watts does it output at 4 ohms? Is it even stable into a 4 ohm load?
Taking a look at your speakers they look like they may have some unwieldy behaviour. Try hooking it up and see. Underpowering a pair of speakers doesn't really do much, as long as you're not driving the amp into clipping with loud listening volumes.
I would however probably pair them with a dedicated amplifier eventually for maximum fidelity. Perhaps check your local audio classifieds for a Quad 909.