not sure what gains you will get from just a downpipe and de-cat, but it is a worthwhile mod as it removes the restriction caused by the standard downpipe and cat, which like i mentioned will help your turbo spool up quicker.
With you already at the 190bhp mark then next step would be to look at changing to a K03s turbo unit and fit a larger downpipe at the same time. personally i wouldnt just change the downpipe if your going to stick with your current turbo.
Also another mod would be to upgrade the standard TIP for a larger better flowing Forge one, but if your going to upgrade the turbo to a k03s then i'd get an AUM TIP instead of a AGU one.
Maybe give R-Tech a call to talk through your power requirements, i recon they will give similar advice