Do I need to update my domain's SPF record? The answer is No.
Sender Policy Framework (SPF) is a standard for authenticating email. It is used by senders to announce mail platforms or servers from which they send email.
An SPF record is not required or needed for improving deliverability or guarding against spoofing, when sending from AWeber and many other email service providers (ESPs). Why? The SPF domain needs to align with the domain found in the return-path header which is normally a domain owned by the ESP.
Instead, email authentication with respect to AWeber and your domain, is fulfilled by the addition of DKIM Records. Read more about how to publish AWeber DKIM records for your domain.
If you still want to add an SPF record for AWeber it will likely be ignored by mailbox providers and will not hurt your deliverability. The following is an example SPF (TXT) record including the aweber.com domain.
v=spf1 mx include:send.aweber.com ~all
Please keep in mind you should only publish one SPF (TXT) record. Use an additional include phrase for each domain you specify. If you're not sure how to edit your domain's SPF records, contact your web host or DNS provider.