Been thinking about this today, and it crossed my mind that the type of case that reaches SCOTUS will probably impact the way this issue, and following cases, get handled. If it's a case where DEA got information, altered it per the policy, and then passed the altered information on, and that information was acted upon with no further/independent investigation, I can't see it surviving a review by SCOTUS, if it even makes it that far. What I think will happen, for better or worse, is that it will be a case where the tainted information will be used as the basis for starting or targeting an investigation. The further information will be something that, on its own, would be legally obtained and admissible. Defense files to suppress the evidence. That suppression will become the issue, and the argument will come down to (1) illegally obtained and/or falsified information from the DEA necessitates suppression of all evidence vs. (2) that information only served to point officers where to investigate, and all other evidence was obtained not due to the DEA information, but the investigation properly conducted by the officers, so it should be admissible.
And here's where I worry about the way the case gets presented. If it comes down as I described, on the suppression issue, you may get 5 votes to say that illegally obtained or altered evidence used by law enforcement as only an indicator of who/where to investigate does not render all evidence subsequently and legally obtained inadmissible. That would be a very bad precedent, and would likely encourage further misconduct at the start of investigations, and would likely create situations where cases are "reverse engineered" to find some legal evidence to bootstrap a case based entirely on the illegal/false evidence.