Re "buzzy", the carbon Tarmac with tri fortezzas at 140psi is a much harsher ride than the Ti Lynskey with GP4000s 25's at 90psi, that's self-evident.
At race pace I have never felt any discomfort on the Tarmac, even after 4 hours, but on a regular ride with lots of sitting up and whatnot, after a few hours I sometimes need to shake out my hands. It's not something that needs fixing, it's just the character of the ride. Nobody gets a Tarmac for long distance comfort.
Yes a tarmac is not a "comfort" bike, but I've been able to ride 5-6 hours on all my bikes with relative comfort and they've a''been setup pretty aggressive, S-Works, CAAD9, Madones. You should be able to ride your bike all day without discomfort, aside from the usual soreness of a long ride. I don't want to "debate" back and forth, but your race bike should be comfortable.
And yeah, I would be willing to wager the 140psi may have something to do with the hands buzzing, I ride 65mm wheels which are real stiff, but I only run 115\120psi.