The reason these are not considered hifi is because they could not meet the relevant DIN standard.(45 500?)
Do not be put off by this though, because some other speakers didn't meet it either, but when paired with an apporpirate source they sound well, I can think of the Type B and the type Ms for example and I believe the Beovox 1000 didn't meet this standard but was well suited to the Beomaster 1000.
There isn't too much to go wrong, as long as the speaker cones and coils are ok, you might want to replace the crossover capacitor with a non-polar type, this will definately improve things - replace one, and compare to the other and you'll soon hear the differance.
If you want something of a similar shape and size then the Beovox 2200 and the Beovox 1100 would be a good option, these did meet the DIN standard, however from what I have seen, getting hold of either at a sensible cost is a challenge.