street racing? yes that's interesting but unfortunately u cant
street race in singapore because if you do manage to find a route
which would have totally NO cars at all (even in the wee hours of
the morning), and if you really want to race, i'm sure u cant
always try your "weight shifting, drifting" at sepang track. As for
drifting, you might think that it's cool looking from the outside,
but in real life when you are inside the car behind the wheel it's
a totally different feeling, and has a whole host of new techniques
that are not easy to master. In reality, drifting has not much
purpose other than wearing out your rear tires since it's not the
fastest way around a corner (but since you are training to be a
racer, especially a street racer i figure u would have known that).
Racing, street racing, touge, any kind of racing, its not the
glamour, fame, or cool-ness that attracts and makes good racers.
It's a deep inherent passion which is not easily extinguished. And
for racing, speed without control is nothing, so lupping in a TC or
SC will not help much if you cannot control the increased output,
and in addition you will have to find an additional way of cooling
your NA engine (assuming, since if it wasnt NA it would originally
have come with a forced induction intake) such as intercooling.
It's not like in Maximum Tune 2, whereby u add parts then the
"orange bars" and "HP" will increase and your car will become
faster. And you should know that its not possible to downshift from
6 to 4 at full throttle because your engine rev needle will end up
outside the window,
But to answer your original question, i think it would be TC, i
like BOV. 
