Track Tuning Imports

I'm wondering can you track tune the new cars???I know with the old carbed non-computer cars you build your motor cam,heads,intake,carb,etc...Then change jets,secondary springs,ignition timing and curve,plug gap and indexing, etc...etc...in the effort to lower ET and raise MPH.Now on the new cars with computers,fuel injection and distributerless ignition can you realy tune them???Do you just build the motor and let the computer control it??I figure you can proably still index the plugs and vary the gaps and when building advance or retard the cam but is that it???And even those,won't they effect the computer???At the track are there tuning variances or is it just run what ya brung???