Which of the following bypass/pipe set-ups is the preferred method?
Which is cooler & are there any negative effects on thrust between the two?

A - exhaust thru center pipe - bypass air between center & outer pipe

B - exhaust & bypass air thru center pipe - fuselage air between center & outer pipe

I'm asking for a Lighting/Titan install. Stock is set-up A - Tam's pipe is B and is 7oz lighter.

Thanks for any educated info.
...Scott