Kurz vor dem Kauf (9400) - Fragen

Hi!
Am short on budget so I need help on CPU.

- Core Duo Processor T2400 (1.83 GHz) sounds very good, but costs 200 Euro
(~$250) more then Intel ® CoreT Solo Processor T1300 (1.66 GHz)

How much difference is there really in 2D and 3D applications (occasional
rendering).
Can I buy a Solo proc and then replace it with a better one in a year or
so - or are the CPUs not upgradeable? Which one is a better value for money?

- 256MB NVIDIA® GeForceT 7800 Go graphics card, PCI-Express x16 costs 330
EUro (~$400) more then Intel® Media Accelerator 950 Graphics Up to 128MB
shared system memory. I'm aware I shoudl forget about the integrated card,
but can I buy the integrated card and upgrade it myself?

The only thing I've replaced on my Inspiron (the last one) was the memory.
Is replacign CPU & graphics adapter also that easy?

What is the high-res display on a 9400 (WUXGA (1920 x 1200)) like? I had a
high-res inspiron before so I have an idea about pros and cons, but what
about the quality, colors, angles... I like the Vaio displays very much, are
the new ones from Dell OK, too?

Application mostly Autocad (2D), ando also some 3D Max (3D)

Wie schneller ist 7800 GTX im Vergleich zu 7800 Go?
Wie schneller ist M 770 (2.13GHz) im Vergleich Duo Processor T2400 (1.83 GHz)

Vor einige Tage hat man den N03XP5c um 1500 Euro kaufen können - jetzt kostete es wieder um die 2000 Euro. Wie sinnvoll ist es bischen Geduldig zu sein und auf so ein Angebot warten. Wie oft kommt Dell mit solchen "Deals"?

Vielleicht könnte mich jemand aufklären,
TIA