Hi mate, I was in your shoes around a year ago, and I posted nothing on here, as I knew all I would get was, 16v, vr6, 1.8t blah blah. So I did lots of research and was all but ready to go down the supercharged route. I then decided on doing bike carbs due to ease and cost and clean looks really. Have you looked at ITB's or bike carbs??
Also there is shed loads more info on Vortex, due to the yanks tuning the 8v a hell of a lot more then here.
A well put together ITB'd 8v could breeze your goal. Would cost £1500-£2500 depending on management and where you have manifolds made, ECU's wired in etc.
Bike carbs done right could see 160-170BHP. Sub £1500 if your willing to do some leg work to get it done. Easy conversion.
If you are interested in bike carbs I can give you more info as I did a lot digging and research before I did mine.
Best of luck to you.