look at the angle of the inlet on the turbo pipe, if it's a 90° angle you have an x90, if it's more like a 45° than its an x8. main difference is ECU/plugs. ... or you could do the easy thing and read the sticker on the ecu
its cool that you're using a steel plate w58 with the weird gooseneck shifter. *supposedly* stronger than the earlier boxes.
what kind of plans do you have for the engine? i'm just curious at this point, we all have big goals but few have broken the 400 mark without some serious work going on. with that in mind, vvti will get you there too but you'll have more available power way lower in the rev range than on a non-vvti engine. formula for quick, cost effective 350-400 whp is single turbo, walbro, 440's and an safc. i bounced around a lot on my build but this is the route i will end up going for now. already have most of the parts collected. eventually you can get real injectors and run an aem to see how far you can push it. pm me if you feel like shooting the shit in detail.
i have a good friend that does this stuff all day long and his advice is scripture for me.