How to change CPU String in BIOS post, reverse engeneering?

Hello, first of all I apologize for my english, it's not my first language.

I'm posting here because your fellows of Hardware couldn't deal directly with the matter at hands, anf they've suggested to me trying again in this section.

I want to change the CPU string posted by the bios. The reason is because a close friend of mine has a computer shop and he has different lines of computers, one of them are overlocked ones (tested very hard to be stable) and he wants the bios to post something like "Intel Q9550: 2,83@3,2Ghz" instead of "Intel Q9550: 2,83Ghz" (the AMI bios doesn't show up the actual speed). The computers are sold fairly, as he explicitly inform that they're OC ones and they offer the best bang per buck, but most of his customers doesn't understand anything about bios, OC... and the only thing that they see is 2.83Ghz in bios post and 2.83Ghz in right-click My Pc, so here's the problem.

I've spend hours and hours reading about this (I'm a casual programmer, C, Java...) but I've not idea about assembly language;  I cannot find a solution. I have arrived to the conclusion that CPUID string (Vendor...) resides in the own CPU, and the only thing the BIOS do is identifying the code associated with that processor and retrieve the information from it, but I am not sure at all, maybe I missunderstood.

I know we can add codes to the CPU patch of the BIOS but I don't know where to find the Strings associated to it. Googling I've reached an application called "Microcode Update Utility for Linux" (http://www.urbanmyth.org/microcode/) that, on the fly, changes the place of memory where this info is stored, so when the OS call for cpu info, it's given whatever we want. This seems that can be useful at changing the strings showed by the OS and other programs, but I've the question if I can launch a boot loader based in Linux, run this code and then pass the control to Windows (i think this is what lilo or grub do isn't it?), I also don't know how to edit the microcode and replace somethings, I know they can be found in http://downloadcenter.intel.com/Product_Search.aspx?Prod_nm=microcode&page_nbr=2&lang=eng .

However, this solution only works partally, we still have the bios post problem, but, really... we can live without it.

The best way will be to reverse engineering the BIOS module (what of them? I also don't know it), I'm lost, can you throw some light onto this matter, or at least direct me to the right way?

Thanks in advance.