The tuning stages vary from 85 to 93Hp for the 0.7T engine of Smart ForTwo.

Stage 1, Stage 2 and Gearbox upgrade are presented below. 

Stock engine specs:

Capacity: 698cc
bore x stroke: 66.5 x 67 (mm)
Compression ratio: 9:1
Turbocharger: GT 1238

Full boost: bar@2000 rpm
Constant pressure:bar
Pressure at revlimit:bar
Revlimit: 6500 rpm

Power: 61hp
Torque: 95Nm

Stage 1:

Engine upgrades:

-Stage 1 Software upgrade

Engine performance:

Full boost: 1.3bar@2000 rpm 
Constant pressure:bar 
Pressure at revlimit:bar 
Revlimit: 6500 rpm

Power: 85hp
Torque: 150Nm

Stage 2:

Engine upgrades:

-Free flow air intake system
-Full 50mm exhaust with free flow catalytic converter
-Stage 2 Software upgrade

Engine performance:

Full boost: 1.6bar@2000 rpm 
Constant pressure:bar 
Pressure at revlimit:bar 
Revlimit: 6500 rpm

Power: 93hp
Torque: 165Nm

Dyno:

Software upgrades:

Boost control is achieved using the OEM ECU and N75 valve.

Use of 95/100 octane fuel is mandatory.

Gearbox upgrade:

The management of the semiautomatic transmission of smart 450 is found in the same file of the ECU, Bosch MEG1.1.
Below is the supported customizing:

*Faster gear changes
*Change of the automatic shifting points/revs
*Uninstall of kick down
*Uninstall of automatic gear shift up at rev limit