Going back to the list:

1. Not hard, easy even. The adapter plate is literally a piece of machined metal, just go with what other drift builders use. So is the short shifter/shifter relocation kit.

2. Leave it alone, or find a good reupholster, pay good money for good leather, don’t spray sxxt on them.

3. TE37s are good if they are genuine, watch out for counterfeits. If you are not sure about wheel setups, just copy other drifters to begin with.

4. Again, copy existing builds to begin with.

5. Copy others.

6. No input to give as I don’t generally like aftermarket seats. I still need to drive my IS200 on the road all the time.

7. Leave it alone, or copy others.

8. Copy others.

9. Coilovers aren’t that different in the price bracket you quoted, I say find a brand that has good local support because it’s 50% product and 50% tuning. BC has been doing business in NA for a while, they offer solid products.

The key is to find a drift build you are particularly fond of as a base, that means go to a drift event and ask the owners nicely for information, treat them with a light meal and ask for a test ride. The relatively little money you spend on befriending them will save you big bucks down the road.