May want to consider a Phenolic resin system. JD Lincoln makes a few that you can initial cure in the range you are looking at and ahve demonstarted Tg's in the 500F range after post!
I agree with others statements that 450F is high for an epoxy.
Good Luck,
Steve
Happy to talk to you about building these parts for you, it is what we specialize in (hollow tubular composite structures).
If some of the tubes are just straight sections, maybe an easier way then molding them. The Y will need to be molded. The method for attaching and terminating bladder...
Been there, done that.
A Sway bar works as a torsion spring. Fiber alignment must be in a 45° bias to provide function. Additionally, you can expect a modulus of around 15Msi with a uni-directional laminate from pre-preg materials. Filament wound UD fiber around 12-13Msi, Braid/RTM would be...