I think the answers are self-evident...since the Crossfire is Mercedes part based and Mercedes (even up to their SLR) uses an auto-stick configuration, so I highly doubt you will see a straight performance stick on a SRT-6.

On the same note and to the question about the power plant's...I would be really surprised if Chrysler comes out with a '06 or '07 Crossfire since from what I have found out 1) Crossfire sales are low and 2) this will be the last a Chrysler vehicle will share numerous parts from their MB brother...