You are right, the torque is quite different, but look at the weight as well. From official Honda/Acura site (Canada):
2009 Civic Si: 1314kg
2009 TSX: 1574 - 1587kg (Auto) / 1542 - 1556kg (Manual)
That's at least 228kg difference (if I take the
lightest TSX), which is about 502lbs!!! If you're talking 0-60, it's about power/weight (HP / weight). The Civis SI has a ratio of 0.0681 vs. TSX 0.0592 (Note: have to convert kg to lbs if using bhp for power). For comparison, a Ford Focus 2.0 2007 has a ratio of 0.053 (
http://en.wikipedia.org/wiki/Power-to-weight_ratio). The higher the number the more
likely it has better acceleration.
In my opinion, the two cars may start off the line head-to-head, but eventually (possibly when the TSX has to shift @ 7100 rpm) the Civic SI is going to over-take the TSX while its heading to 8000rpm red-line.
Based on discussions I've read about HP & torque debates, I feel that if you're looking at all out performance where you can rev up to red-line (e.g. reving it up and dropping the clutch and not daily driving scenario), the SI will beat the TSX because of the relatively similar HP figures, but with the SI having much lighter weight.