I like the 90 grainers from Cor Bon.They are smoking fast!!
But I recon that the lower sectional density and mass mean that the velocity peters out and penetration is less than a larger bullet with an equal loading.
http://www.hipowersandhandguns.com/LowPenetration.htm
Corbon 90-gr JHP +P: This ammunition usually averages around 1500 ft/sec from the Hi Power and provides decent accuracy at 15 to 20 yards. Lightweight bullets for caliber do lose velocity quicker over distance than do heavier ones, but that should not be expected to make them any "safer" in the event of a miss. In 10% ballistic gelatin, penetration is normally in the 5 to 6" range. This round expands reliably and consistently fragments.
EDIT: And to keep this related to the original post, I would stick to the .40, due to the fact you can load a larger and higher grain projectile in it. The 180 gr 40 has a higher sectional density than a 125 gr 9mm projectile (.161 versus .141). Even with the added velocity, the .40 usually rates better for penetration in ballistic gelatin. Not to mention any bone, etc (see LDP's post quoting the medical examiner). That, and the cost is far more attractive.