I agree with Yankee and the others. Lightening the springs too much could be a little scary I guess, but the smoothing of internals would really have to be botched to cause issues.
Also that whole argument about if used in a shooting, and you changed the trigger. Are the lawyers really gonna open up your jframe and check the spring? Or break out a Guage and check the pull? I doubt that. Besides I have seen huge differences in the pulls from the factory (Kahr is the worst) literally 3-4 pounds difference between one gun and the one beside it in the case. Now some of that may be due to it being dry fired by customers from having been in the case longer, but hey I would recommend a lot of that any how, it is how I built my finger up.
The others are right, get a trigger stoning and/or some spring work and you will love that beautiful S&W more than you ever could that polymer abomination (I don't hate Rugers for the record, I own a Bearcat, SP101, 10/22, etc just not an LCR). Also the new bodyguard 38's from Smith have or at least had a short stroke issue (design flaw). Look on YouTube for "don't buy a bodyguard" or something like that and you should be able to find a video or two shows you just that.