Does the Ford 6.0 PSD need an exhaust brake?

[sreigle]

Supposedly the 6.0 PSD with the new 5spd automatic has the tow/haul and some kind of downgrade compression braking as well as "smart" downshifting when braking on a downgrade. I've been hearing this eliminates the need for an exhaust brake. I'm wondering if those of you with this combination agree with that. We have not yet towed with ours and won't be in any mountains for a couple of weeks and don't really want to be in a tight downhill situation where I am standing on the brakes to keep the speed down. Would appreciate experiences on this. I know the 7.3 benefits from an exhaust brake. The 6.0 owners manual says it's not needed and, naturally, might void the warranty (I suspect they all say that).

Steve and Vicki Reigle
'03 F350 SC SB SRW 6.0L PSD Auto tranny; '03 3295RK