I have used Warmifier. It was a staple for years. But being essentially a tube emulator it's got a fairly limited palette compared to more versatile exciters that have come along since. Chances are you've already got third-order harmonic distortion covered via your amp sim. What you want is to add distortion to high frequencies in particular, so you probably want to look at multi-band exciters.
There's an affordable one from
Audiority that combines multi-band overdrive with a limiter. I tried it awhile back but it must not have been terribly impressive, as I don't recall much about it. There is a demo, though.
Another (free) approach is the DIY homebrew method: clone the guitar track, put a high-pass filter on the clone followed by whatever distortion plugin you like. Mix that back in with the original to taste. Try adding a subtle chorus or modulated reverb to the parallel track.