Enable RTS flags?

I've seen reports of elm make running substantially faster when using the RTS flag to configure Haskell's runtime options, e.g.

elm make +RTS -A128M -H128M -n8m -RTS src/Main.elm

We could do this when invoking elm make from elm-test.

It'd be a tiny code change, but I'd like to see some numbers to back it up before committing to it. If anyone would like to run some benchmarks and compare how fast things are before and after using the above (and ideally a few variations of those settings) specifically to run some elm-test suites, please post them here so we can discuss!