Ok dude, I'm going to tell you this straight up. You need to shut up and listen to what people are trying to tell you. You're so full of misinformation that it's actually sad.
If you bore an 81mm bore to 84mm you won't be able to run anything on it. If you get a block that comes with 84mm bores, it's not going to break. If you want to spend an extra thousand dollars, sleeve your B18 to 84mm. Huge waste of money. Huge. That could pay for most of your turbo.
Next, getting 200whp all-motor will require you spending most of your budget and will require mods that are not going to be turbo friendly. The cam will be high over-lap and low duration which will blow all of your boost out of the exhaust ports on the compression strokes. The head will have to optimized to flow at high rpms and the flow will be geared towards an all-motor application. The compression will be so high that you'll more likely than not have to run race fuel or spend several hours on the dyno at $150/hr.. You'll need a header that will cost $1k by itself. You need to make up your mind on which build you want.
If you don't do your own research your engine will blow up within the first few thousand miles. I don't buy for a second that you have any experience with engine building. Maybe lawn mower and weed eater engines, to be fair.
If you aren't ready to learn, you won't get any further answers. We help people who help themselves and leave those who want to be spoon fed to fend for themselves.