I would guess close.
I have the Mag SRT and just got a SRT6
Numbers appear very close.
Speaking strictly stock the 8's usually finish the quarter a tenth or so quicker but the 6s a few MPH faster...so it is just about a toss.

I would say it comes down to your preference. The Crossfire is pretty small so if you do not have a 2nd vehicle you are a little limited on cargo and passenger capacity..

I recommend BOTH!