Which way do you mean straight? Had a 996s a few years back and I fit carbon termis to it and spent a long time messing around trying to align them. My problem was that the righthand can was about 1/4 inch further rearward than the other one. Used to really bug me and I spent ages undoing everything and pushing and pulling til I got it right.I still find myself looking at other peoples 996 and checking out whether the cans line up ok.
Mine are slightly wonky as well - Nelly did mine for me, said if I wanted to try straightening them it would be a job for one long winter evening and lots of fiddling. Can't say I've ever bothered, they still bug me from time to time but they make all the right noises so I don't worry too much.. maybe one day when I've got some time on my hands...
By 'straight' I mean centrally aligned with the reflector. The left silencer outlet is higher and further away than the right. I've tried loosening all bolts getting my g/f to hold them in position and then tightening them up but no joy...
Nevermind, maybe this is just another little quirk that we have to live with...