Been a long time!...Need some Guru input.

[RC-Monster Mike]

Like Harold mentioned, pretty much all 1/8 buggies use Mod1 gears, including the mbx4. Our Mugen motor mount is a direct fit on the mbx4 as well, and our 50x150 1 piece battery tray is the universal tray that is used when a vehicle-specific tray is not offered.
Also, let me know when you are ready to upgrade - I have a new, converted mbx6 MSpec buggy that I used for trade shows for sale. It has never been run. :)