[Radio Wrangler]

Monacor are reputable makers of good quality speaker drive units. Those have soft surrounds.

speakers with soft surrounds rely on air pressure within the cabinet to provide their restoring force. This could be a sealed cabinet, or the back-pressure from a ported cabinet. Speakers with stiff surrounds provide all their own restoring force and were made to work in very open cabinets. The springiness and the mass of air driven by speakers creates a resonance, and cabinet design and surround design is intended to place this resonance where it is wanted.

Whether this speaker matches up with the simple crossover and tweeter you already have is unknown. Whether they will sound good is also unknown. The only way to find out is to try them. This unfortunately doesn't fix the risk of you wasting your money.

If you aren't fussed about buying new, people are giving away quite decent second hand speakers for free, if you look around.

David

EDIT: Cross-posted with Nick.... there you are, an offer of free ones right out of the blue!