Frames: aluminum vs. steel for IDPA

[MAGTF]

Need some advice selecting a Kimber. I plan to use it for IDPA and home defense. I'm debating between the TLE or the Tactical. I like the extras that come stock on the Tactical (magwell, ambi safety), but it is a few ounces lighter than the steel-framed TLE. Otherwise, they are very similar.

Will I notice the difference in recoil/speed of re-acquiring sight picture?

Today I shot a 4" Tactical and a 5" Eclipse at the local range and could really tell the difference in recoil. Was that primarily due to the shorter barrel, or the aluminum frame?

Thanks in advance.

Semper Fi - MAGTF