To add to what the other person said, if you are not using your own IP (as in a VPN), then that isn't much of a concern as long as the connection between you and your VPN server is properly secured and encrypted.

There are many layers we could talk about when we say "privacy".

First about IP:

• publicly broadcast your IP: this is done if you announce yourself to one or multiple trackers. Their jobs is to list the clients sharing specific torrents. They maintain a list of IPs and respective progress on the torrents so all clients can connect with each other depending or their needs. You can use this to bootstrap your client need and leave instantly if you don't want to be found (defeat the purpose of torrent...).
• there is also the DHT protocol that will distribute the list of IPs amoungs clients so no one has the full list. I am not well versed into it yet. You can search for more info.
• finally PEX is a peer exchange protocol to get new clients from the one you already have.

There's also traffic monitoring:

• like https you probably want to encrypt your traffic if you don't want people to catch it. Most decent clients have the option but it's never set strictly so the choice of encryption is optional on default. ISP love to sniff your traffic, I usually don't care but whenever I need to download an other Linux distro image I need to use a VPN or be throttled. I'm not even doing it to hide anything, just to use my internet connection...

The op question makes no sense to me though. Torrents are just file you want to get/share, there's no privacy involved in that. Maybe they meant torrent clients.

Your first and second points are incorrect.

First, no your ISP cannot see anything if you are using a VPN. They only see encrypted packages and might be able to determine that you are using a VPN but they absolutely cannot tell what data you are sending or receiving.

Second, I have never experienced that a ISP in Germany throttles torrenting, even without VPN. Torrenting per se is not illegal, you can download Linux ISOs via torrent. We still have net neutrality in the EU and in Germany. Throttling torrents would violate net neutrality and would be illegal AFAIK.

Sorry but this just isn't really correct and assumes the ISP puts in a lot of work to track people down.

They are not the ones enforcing DMCAs from illegal content. That is performed by cybersecurity companies that crawl through IPs in seed swarms and then report that automatically to the ISP if it registered within their IP range. This is a page from one of those companies advertising this service. You can see the report that Comcast gives out and it sites who reported the violation.

Also, yes a lot of VPNs do actually remove logs. Can't report to authorities what you do not have, although some areas do have retention logs which is why you should be using a VPN service that hosts a server in a country that doesn't care about that (I point mine to Canada depending on ping and that works for me). Lots of VPN services have third-party audits to confirm their privacy statements, and I utilize one that has no information on me besides the email I signed up with (and could use cash/crypto payments if I would like for extra anonymity).

Also, there are sites that check for IP leaks like this one which can confirm you are showing only the VPN IP address. As for the port issue, they also allow for port forwarding on a lot of VPN servers so you don't need to be utilizing any ports directly to your connection, only to the server and then gets forwarded to a WireGuard port to finalize the connection.

I have torrented absolutely astounding amounts of data with my VPN active and have had zero issues. Then, the moment I accidentally disable the VPN for one reason or another and keep my torrents active, I received a DMCA for two torrents I was running at nearly the exact time I disabled my VPN connection.