I recently got a new (to me) Ti Merlin Solis with carbon seatstays. Coming from my Al Fuji, the rear of the bike feels way more flexible. On a hard sprint, I can even feel the rear wheel camber. It's not slipping in the dropouts, but the entire rear triangle of the bike just flexes towards the drive side. So... I was thinking, is there anything I can do to stiffen that part of the bike? I was thinking of swapping out the Ultegra Octalink crankset and bb for a 105 Hollowtech II crankset and bb (I have the crankset on my Fuji, but it has a pressfit bb, so I'll need to get an external bearing bb for the threaded bb of the Merlin). What benefit would this bring, if any?

THe other day, I was taking off the crankset from the bb (it uses a self extracting 8mm allen bolt), and when I was putting it back on and torquing the crankarms onto the bb, I could see the bb flex towards the NDS. It flexed quite a bit (maybe 2cm). I'd estimate the torque I put on the bolts at about 35-40Nm, so that should give you some sort of a sense of the flexibility of the bb.