We should have one thing in mind, starters usually don’t have the skills and knowledge (and time) to overhaul a former state of the art speaker. Older speakers have often broken surrounds, and stuff like that. Forumers tend to suggest speakers like the Pentas. But for an absolute beginner, this speaker could be a nightmare. Young fellows are not used to fix things, they know to download an update. 😀
To refoam 4 woofers of an Redline 140 pair is tricky and not an easy exercise. So, the task of refoaming 8 midrange speakers of the Penta must be a torture for a beginner.
To rebuild an ABr passive unit is another horrible thing people should avoid.
That’s why I think a fair suggestion would be the redline 60,2; Beovox S 45 (first generation). These speakers are affordable and easy to get. You don’t see speakers like Beovox 5000 MK III often on ebay, maybe twice in a decade. 😉