my r34 gtr made 248rwks with mines ecu, pods, exhaust and 1.2bar.
ran 12.8 at 109mph at willowbank with 1.90 60 ft... but didnt really pull that well top end with the mapping in the mines ecu...
so your 278rwks is great , should do a mid 12 if you launch it hard...
since then have gone a little silly fitted hks2530's & hks dumps, 700cc sard, nismo fuel pump and reg.z32afms and super induction kit, power fc....
hope for high 11 or low 12 now even on close to base map in the power fc.
i will be going to the track soon if it stops raining in brisbane everyday....