Toshiba Satellite Pro 4600 CPU Upgrades

I'm new on here so please bear with me with my first post......

I am hoping that someone may know the answer to this question - it seems surprisingly difficult to find the answer on the net.

I have a Satellite Pro 4600 laptop - with a mobile P3 700 cpu.

I know that I can upgrade to 850 no probs but I wonder about compatibility with the P3-900 / 1000 CPUs (The 100MHz system bus variants with 256k L2).

All the parameters should be compatible - with the following possible issues;

1. They use a higher voltage (Motherboard handle it?)
2. The TDP is a lot higher (cooling issues?)
3. BIOS compatability (eg. max multiplier)

The BIOS is the latest version, released some 8 months after the release date of the P3-1000's, so that's positive.....

Any ideas anyone?

Thanks, Ollie.