Exactly. I should have been more explicit but that's what I meant about "adding another module". You would import
Control.Monad.Par.IO and get runParIO + liftIO but NOT runPar. This requires doing a newtype over Par to create the liftIO instance for one and not the other (and preserve Safe Haskell). It's a pain but it's no problem. Both types Control.Monad.Par.Par and Control.Monad.Par.IO.ParIO will expose the same interface (i.e. have instances of the same classes -- ParFuture, ParIVar...), so generic algorithms like "parMap" will still work for either.