I doubt Oleg will implement PhysX or Havok as they're not interchangable between ATI and nVidia cards. In June/July this year nVidia announced that it will wanted to allow PhysX to run on ATI cards, ATI turned around and said Na...we'll go the other way... and said it will only support Havok, which is owned by Intel BTW. Very messy situation.
I see Oleg implementing his own engine, posibly using an open source API like ODE (
www.ode.org)
If your wanting to upgrade, I'd keep saving and wait untill SoW is here.