Mega Drive 2/Sega CD 2 Region help

Hi all

My brother has a Euro PAL Mega Drive 2 and Mega CD 2. I downloaded a heap of US SegaCD games for him, but the various software region converters dont seem to be working on the images.

What we want to know is if it's possible to relatively easily region mod the Mega Drive 2 or Mega CD to a US model.

Here are the options I've thought about, if anyone can tell me which are possible that would be a good start.

A) Some sort of Action Replay Cartridge/special boot disk to make the pal machine run US games

B) Flashing the MegaCD Bios with a US bios (if using this method is the Mega CD 2 bios socketed or soldered onto the motherboard (im hoping socketed to make it easier but have my doubts)

C) Some kind of wiring/soldering mod to change the region of either the Mega Drive 2 or the Mega CD2 to a different region.

D) Any other option you guys can think of.

He has 3 Mega Drive 2's so we are happy to convert 1 permanently into a US model genesis if this is possible and will get the desired result. He doesn't have any mega cd games yet (just got the machine) which is why we're happy to mod that too, to permanently be a US machine if possible.

Thanks for your help in advance.

Only hardware way is replacing the existing BIOS with some other region one, or doing a BIOS hack. One other way, which is rather convenient and has many other benefits is the Megacart. I have one and it kicks ass. Its a flashcart, RAM cart and region change (for MCD) all in one.
Does the Megacart work with all/large majority of games?

Any idea where id get one (I persume ebay would be able the only place) and what they'd be worth?