What in your opinion would be the best way to build up NA a D series engine to compete, on the road performance wise, with NA DOHC engines of similar capacity?

I/H/E all go without saying.

The D series in question is a '99 D16Y4, stock 88kw.


I realise some of you may just think that a conversion or boosting is the best way.
But thats not what im asking so please restrain form posting unproductive useless comment. Cheers.