Have a search through the 16vmini forum.
I have read some of the builds on there that have used these kits.
The MTB2 kit increases the front track but I'm not sure by how much.
Allspeed make a subframe for the B18C and suspension parts that retains the front track.
Both fit in a standard length round nose mini. But it is really tight and many of the builders comment on knocking sounds on acceleration/deceleration. Big engine - little car
The B18C Type R engine comes with 5 speed and LSD & 199 BHP
It does need the final drive changed if you run little wheels though
