Dual G5 2.3 Ghz Or 2.7 Ghz Options

[Milca]

Hello everybody
I’m about to buy a dual Mac G5 in a Macintosh store.
I’m kind of deciding between Mac G5 dual 2.3GHz and 2.7 Ghz
So basically this is my first question: Is it worth to pay 500 $ more for 2.7 Ghz.Another word - is there a really big difference between those two types?
and if I get the 2.7Ghz - will I be able to use that extra speed?
I’ll be running
-DP 4.5
- hopefully Pro tools
- Ableton live 4.0
-Waves platinum plug- ins
- Native instruments komplete 2
-Silver orchestra
-BFD drum module
-a lot of spectrasonics products (including stylus, trilogy, atmosphere and and libraries like back beats and vocal planet)
and couple of other plug-ins

Second question is about RAM.I’m getting 1 gig of extra RAM – anyone has experience if this should be enough?

I would appreciate any answers
Thanks for your time.
Milan