Turbo....

TT5.9mag said
With a slant 6 having a narrow powerband, 1500-5500 or so, if you’re not at full boost pressure or damn close to it at 3000 rpm you have the wrong size turbo. And usually a small hit of nitrous is used initially to spool a turbo sized larger than optimal. So if you’re racing it, I suggest using the nitrous at the hit and killing it before peak torque. Let the boost take over from there.

I've done a TON and I mean a TON of reading on turbos. From what I've gathered, for best street acceleration, it's actually best to choose a turbo that's just a tic smaller than you need. Similar to how some of the diesel boys do it. The smaller turbo spins up quicker. But too small and the power benefits fall off drastically.