If you have your own opt-in list, that you built yourself, you can use plain old Postfix or Exim. The key, besides setting up rDNS/DKIM/SPF/DMARC, is to slowly build your reputation. You don't send 10K+ emails on day one.
Suggestions:
- use any of the various warm up IP schedules you can find online
- send regularly
- make sure your mailing list software can automate bounce/feedback loop processing
- get contacts to add your sending email to their contact list
- provide detail instructions with pictures on how to do so
- use program logic for the big four (AOL/Gmail/Hotmail/Yahoo) to send people specific whitelist instructions based on domain (@gmail.com goes to the Gmail "add to contact list" instruction page).
- do the same if your MLM (Mailing List Manager i.e. Mailwizz, MyMail, etc.) can detect the MUA (Mail User Agent i.e. Outlook 20xx go to the Outlook "add to contact list" instruction page)
- encourage contacts to regularly send queries back to the you by replying to your email(s)
- tailor your messaging based on a contact's behavior so as not to send you message to your entire mailing list (if your MLM supports any form of automation & tagging)
There a few more things that I do that I can't reveal here.
Now if you're spamming, it's going to cost you. Nulled PMTA/Interspire with a range of IPs aren't going to cut it. Snowshoe is not hard to detect. Most of those guys laugh and ridicule those types of setups.