OK heres the tutorial for fitting these two fuel tanks to your MT2 (will probably work with other Fun Factor vehicles).
The tanks are here:

http://www2.towerhobbies.com/cgi-bin...24&FVPROFIL=++
http://www2.towerhobbies.com/cgi-bin...e2&FVPROFIL=++

Although these tanks are 125cc and 100cc respectively, they both have the same mounting dimensions, the only difference is the larger OFNA tank is higher than the HPI.

The front of the tank will mount on the upper chassis plate and the rear will mount on one of the upper plate support stays.I have included some pics to help out.

Step 1:
Remove top chassis plate and mark out where to cut as in pic 1.
The line is 16mm down from the EDGE of the chassis mounting hole.
Also remove the 2 chassis plate stays left behind on the left of the chassis.

Step 2:
Cut off excess material and smooth with file. See pic 2.

Step 3:
Drill mounting holes in the top chassis plate and the main chassis where indicated in pic 3.
Top chassis plate hole 4mm up and 20mm across.
Main chassis, 35mm across from bend and 40mm op from large engine mount hole.
Countersink hole from underneath main chassis.

Step 4:
Screw chassis plate stay to the rear tank mount hole.
Screw tank down and check for clearance between it and upper chassis plate, if you are using fuel tube to allow your tank to move slightly then make sure tank has clearance from touching upper chassis plate or you will find it may rub and possibly rub a hole right through your tank, dont be lazy and file some more off!!!
Now check the clearance between the front of the tank and the steering arm, you may have to file off a mm or 2. Dont worry theres heaps of spare material there as the outside hole on the arm is not used anyway. (Last pic)

Thats it, after complete installation you will have longer runtimes!!!

Hopefully I havent forgotten anything. Any questions just ask.

Cheers.
Azzman