It isn't that it's outdated trash, it's that most electronics become outdated trash. It has a radio input which is based off your antennae, so it's the same. The only difference is going to be how many watts per channel, it's not going to beat 50w x4. The eq is what 5 band, compared to 13 band on anything new? How many amp outputs does it have, probably one or none? Does it have a camera input, nope? time alignment, probably not? I can find $100-$150 head units from every manufacturer that do. Some older electronics can function under special circumstances which make them valuable in the right situation, this isn't one of them. The only reason to keep it is because it's nostalgic. Technology wise, it's outdated trash.
Do you really have tapes? Buy a $5 flash drive that 90% of all new head units have inputs for, and you can SKIP SONGS. You can organize all your music in folders, and not just have em on one long line that have to search through to find. Tapes get ruined, are annoying, don't keep quality, and one tape takes up about 5 times as much space as a flash drive.
If you're putting this in an 80s/90s car because you just love flock of seagulls, with neon green hotpants, or too legit to quit and hammer pants, then more power to you. Otherwise, you're going to spend on parts and time what it would cost to buy a new one, all so you can have an alpine name brand and a tape player. Don't take it personal. They were being funny, and trying to tell you not to waste your time and money, but you want to for a reason that probably doesn't even matter, and doesn't make sense. Dude, you've been working on this for 3 1/2 years???? Let it go.