I would definitely convert all your old cassettes to CD or MP3 regardless what type of car radio that you want to buy. The quality of CD and MP3 is much better than cassettes. Cassettes are analog recordings, whereas CD and MP3 are digital recordings. When you convert the cassettes to digital, you will hear how crappy they actually sound. There will be hiss, tape crunching sounds, and other analog noises. Although, with a good digital program restorer you can probably restore them to digital. But, it takes time, and learning the digital program. The big underlying problem is that cassettes will eventually be eaten by your Car Radio, and possibly destroy it. Cassettes build up static, and it is just a matter of time. Then, trying to get that eaten cassette out of your radio, will make it is useless. It will never play the same again, and it will constantly be eaten. Therefore, it is best to transfer them to CD or MP3. If you have a computer, you will have a backup or your favorite cassette for life. Cassettes and 8 tracks are totally obsolete. They do more damage to your car radio than they are worth in my opinion.
I got a cassette with my new wrangler back in 1997. My new wrangler started eating my cassettes almost immediately. I then added a 50 CD disk changer to my Wrangler in the trunk. My cassette player was useless and obsolete. The reason I brought the cassette player instead of the CD player is because people steal the CD players, and I didn't want someone ripping my CD player out of my new Wrangler, and destroying my dash in the process. I've had that happen in all my other cars. The good thieves will even cut your car alarm under the hood. I once found bullets and drug paraphernalia after my radio was stolen while my car was in a gated community in a car port directly below my apartment. Those drug users are desperate. But, no one cares about stealing cassette players. My 50 CD player became obsolete too. I quickly filled it, and the heat eventually destroyed my CD's in the trunk. My ultimate final solution was MP3, and a removable face plate on a great one din CD/MP3 player with bluetooth. No one wants to steal a Car Radio without a face plate. Because once they steal it, it is almost impossible to get the face plate, to sell it for their drugs. Stock CD players are a great target for thieves. When your dash is smashed only once, and you spend $1000 dollars or more, replacing your destroyed console, and replacing your radio, you will see what I mean. Just a word to the wise in drug infested America. It doesn't matter where you live either. I live in very nice areas. But, this is where the drug users know they can get their drug money by stealing car stereos.