Cubase 5 ( & 6 when it happens ) with Mac Pro

I’m thinking of changing from Pc to Mac Pro ( dont want an imac) need it to be of use for 5 years,
& wonderd how well Cubase 5 worked on them.

After reading a few peoples comments on the internet it seams as though “Not very well” is the answer.

I hope Cubase 6 will work better on the New Mac Pro 8 core computers.

First of all are Mac’s really that much better than Top end Pc’s such as Scan Pc
( ).
I want to be able to have 3 people jaming on virtual synths, and record audio from a guitarist at the same time, with effects and other vst’s sequenced and playing without the system Screwing up and Crashing (really fed up of that).
Which would be best a Quad core or 8 core for my home studio.
Do they work as 64bit or 32bit and can you make them dual boot for Windows OS.
Can you put an extra Hard Drive in them on purchase.
They only have 5 Usb ports so can you pre instal more as would use them up instantly (hubs are no good as they share the same IRQ).
How much Ram to have ( stupid question as usually as much as you can get).
Which audio interfaces work best with them Was thinking of £300ish ( dont need lots of live inputs ).
Which connection Fire wire or Usb.
Do most of the Vst’s work on them.
Can you use effects and synths from Cubase in Logic and from Logic in Cubase?