Lets not all answer at once guys!

1st of all i have no idea which is the best turbo/ housing etc even if such a thing did exist - what would be ideal for ultimate power would not be ideal for lag etc and one drivers acceptable amount of lag is anothers acceptable lag there is no "right" way or "wrong" way - so its a balance/ compromise between ultimate power and lag

you may have to change parts/ setup to get the best results for drag or track or road or settle for some sort of compomise

here is some ideas / comments -

if you heatwrap or ceramic coat your exhaust manifold it will get more heat into the turbine - reducing lag

turbos don't need a tuned length exhaust - the shorter and fatter the exhaust downstream of the turbine, better/ the less lag - a side exit 3 or 4" (single) side exit exhaust with straight-through muffler will reguce lag/ may increase top end power

the GT series is more efficient than the T series and you may be able to go smaller than expected (thus reducing lag) and still produce the required gas-flow / top/ end power.

A modern electronic digital boost controller will outperform a mechanical actuator/ older controller - it can reduce lag and can have much more precise control over peak boost pressure as well as making a big difference to the midrange power/ torque

I always feel the traditional intercooler is a bit big and inefficient a smaller one with a lower internal volume may produce similar top end power but with less lag - especially if you ran a water spray (external to the intercooler) - an air/ water chargecooler may be the way to go - hoses would be shorter, the core would have an even smaller internal volume and you could have an ice tank for drag racing

i don't rate k&n's even if they have a heatshield and cool air feeds - you're far better off with a fully encapsulated CAIS - Venom, BMC etc

i like the spec of your car!- did you do/ choose the mods? what type of anti-lag and launch control do you run?