[Beedub]

btw this kit is rated @ 450hp :-)

heres the bumpf from the the gpower site

G-POWER supercharger system SK I "Sporty Drive"
Basis: Z4 M, 343 hp (252 kW) increased to 450 hp (330 kW)/ 460 Nm
consisting of:

Belt Drive:
ultra stiff CNC shaped supercharger bracket system made from cast aluminium including an extended support-aggregate belt drive for the supercharger´s drive;

Air Intake Manifold:
racing air filter;
flow optimized clean air intake with large diameters made from cast aluminium;

Forced Induction/Intercooling:
ASA T1 518 supercharger with centrifugal clutch ASA K07 (optional);
supercharger lubrication through bypass from motor oil circuit;
air/water recuperator with front mount intercooler;
engine inlet manifold made from cast aluminium;
pneumatic, load-dependent boost regulation
boost level approx. 5,8 psi rel.;

Engine Modification:
6 racing spark plugs with modified heat values.

Fuel Management/Electronics:
adaptation of the software of the standard electronic engine control unite (BMW OBD remains fully preserved), enabling an unlimited top speed according to the capacity of the tyres;
6 x fuel injectors with enlarged mass flow.

interestly this blower needs nearly 6psi to make the power the ess unit does @ 4.5-5psi, this is where the flow characteristics come in for each blower, that big vortech can make upto 750hp with no mods just a pulley change, the ASA unit needs to be swapped out to the top units, this unit is maxed out by 550hp..... That said our Vortech units lack Tq, what our cars need imo..... This kit @ 450hp will gain significantly in TQ due to the nature of the asa units...... make no mistake, this will be a very fast car....

interestingly they tune with MAF in place.... i say it again the hardware looks fanatastic!!
look forward to seeing how the AFRs look on this....