Hello Salona,

I've helped with BMW 5 series Roadster which you can see here

http://www.haynes.co.uk/forums/showthread.php?t=119

As you can see this car was made much wider to fit the 2.5 straight six but the four cylinder engines will fit in the standard chassis, the gear box would require modification to the chassis, similar to the MT75 mods here

http://www.haynes.co.uk/forums/showthread.php?t=53

The front and rear hubs are substantialy different to the Sierra set up.

The fronts require a fabrication like this

http://i126.photobucket.com/albums/p...ntupright4.jpg
This would bolt to the fixings for the front strut

I haven't done any analysis on geometry yet, it may be some time as I'm right in the middle of a new book.

At the rear the rear hubs bearings are part of the huge and unusable trailing arm, I think ther best way to deal with this would be to make (or have made) a bearing carrier to receive the hubs which would bolt to the rear upright like the Sierra.

I'd ask on the forum too, I know some builders are using BMW bits and might have some more practical advice for you.

If you need anything else don't hesitate to get in touch, I'm here most days

Cheers

Chris