Stock housing with K &N insert, replace all vacuum pipes and fuel trap. Service inc fuel filter.
That's what I always do with my new purchases

I had an HKS downpipe on mine and a kind of cherry bomb silencer, changed silencer for RC40 rear box type. HKS changed when flex joint broke but kept for repair as much better than stock.
Unless you have diagnostic reader, fuel pressure measuring kit and CO meter I would replace the service items assuming the worst (vacuum pipes and fuel trap are service items and account for the highest percentage of issues on SPi running conditions).
Also worth reverse flushing the radiator and checking temperature gauge reaches the white spot just below N when warmed up.
FS