That looks like an eBay kit that likely started life being a kit for a 3-series. JUNK.

There are no 4.8is turbo kits on the market, nor would I expect any manufacturers to build one.

If you want to turbo it you'll have to have it custom built. Cost will be well over $10k but it would be possible.

I would consider a supercharger setup, likely a bit easier and cheaper.

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2002 X5 4.6is - Titanium Silver / Black Alcantara - Dinan Stage 2 - Bilstein/Eibach - Brembo BBK ----SOLD---
1993 318i - Brilliantrot / Tan - bone stock daily driver