Well, I did this with a set of Buddy Club N+ coilovers a couple years ago and finally got around to tossing up some pics. Here are a few notes:
 
1. Don't do this with Buddy Club N+. They are way too soft and the TL squishes the springs way too much. The USDM spec Tein FLEX would be a great choice. The springs are slightly firmer than the SS for a TL so handling and lowering ability would be much improved from the SS. The Racing Spec would be a decent choice as well since the springs are rated a little higher than the N+. This would be like having SS that you could lower more. I'm hard pressed to recommend anything other than these though. Tanabe SOC would be too soft. SS from a TSX would be slightly softer than the SS for a TL in the front, but not the rear...not a good choice.
 
2. All you really need to do is remove the studs from the TSX top hats and add a couple washers to the rear lower shock mount. Sus that uses OEM TSX upper mount could probably use TL OEM upper mount instead. Keep in mind that deleting the upper mount studs will mean you can't run a strut brace. My upcoming brace should solve this issue though.
 
3. The pics of the car super slammed are for showing off only. The last pic is where we left the car for driving.
 
That's all folks. Here's the link to the pics.
http://www.heeltoeauto.com/files/tech/tsxsusintl/index.htm
 
 
Marcus