Full disclosure: I'm not sure there's a marked difference in my success depending on modules.

I hear people go on about how radar derp and seismic is basically mandatory on all mechs, and target info gathering if you have a third module slot. And while I do use modules, I typically just scatter my random collection of modules (360 targeting, advanced zoom, seismic, etc) among my mechs. Advanced zoom is mostly for snipers, of course. Target decay is a HUGE gamechanger for LRM boats. But other than that? Meh.
I can see how it makes a big difference among the top 1% of MWO players, because the margins of error are so small that any advantage is very significant. But that's not where I'm at.
Maybe this just reveals that I'm the most clueless bus driver in the steering wheel underhive, but so be it.

Will anyone else admit that it doesn't make a huge difference for their effectiveness? Or are you all 2 l337 4 me?
PS: Tried to get some data on WLR based on Modules equipped, but it appears that part of the personal stats was so broken that PGI has stopped gathering data.