Nope. I got an e1405 and I have 4gb of memory in it - no doubt yours will do fine with a 4gb set. One stick is on the bottom, the other is probably under the keyboard so beware. It's still easy to get to though.
And yes, you can upgrade to a T7200 - make sure you buy the correct socket for your computer. the processor (if its anything like my e1405) is EXTREMELY EASY to get to. I was surprised after working on so many HP's. Make sure to add some Arctic Silver 5 or equivalent to the processor/heatsink. Buy the processor off Ebay - you're looking at like 89.95 shipped.
With a T7200 you can run 64bit operating systems too. Not with the T2300 though.
Oh and you'll probably need a bios update for the 2x2gb sticks of memory.
Edit: I take that back, you may be limited to just 2gb of memory. I just checked crucial.com and thats what it said.
The memory access is on the bottom side of the laptop. There is a small panel that can be unscrewed and there are currently two 512mb modules.
I am not planning to run the 64 bit OS because some of the application I am using does not support it, plus I have my desktop on 64 bit OS. Since I am not going to use 64 bit OS getting 4gb of ram is not useful because only 3.25gb will be used. So can install 3GB of ram?
The latest BIOS update was A17. All it says in the description is
Fixes/Enhancements
------------
1. Added support for newer Intel processors.
2. Fixed issue that some 1394b Express cards will cause an intermittent no post.
So I assume that this update will work for more than 2gb of ram.
Also, I found this on the Dell forum - "the E1505 is a Socket M system and WILL work with the micro-FCPGA T7200, T7400 and T7600."
However there are two numbers for each model
SL9SE 2.16 GHz T7400 2 667 MHz 65 nm B2 4 MB Micro-FCPGA N/A
SL9SK 2.16 GHz T7400 2 667 MHz 65 nm B2 4 MB Micro-FCBGA N/A
SL9SD 2.33 GHz T7600 2 667 MHz 65 nm B2 4 MB Micro-FCPGA N/A
SL9SJ 2.33 GHz T7600 2 667 MHz 65 nm B2 4 MB Micro-FCBGA N/A
Which one will work?