M6850-FX

I have a Gateway M6850-FX laptop with this
http://support.gateway.com/s/Mobile/...6270Rsp2.shtml
motherboard, and was wondering if anyone has any suggestions for a CPU
upgrade. I've looked at the specs for the current CPU (Intel® CoreT2 Duo
Mobile Processor T5550 @1.83GHz), and tried comparing the package type,
etc., on the Intel processor site, and am greatly confused. Does the
stepping have any effect on the upgrade; i.e., is the stepping only
internal, or does it affect the motherboard?
Any suggestions would be appreciated.

TIA,
SC Tom