Heads

If you have 1.88 heads, and do nothing but machine for 2.02’s and the accompanying “bowl cut”....... there will be very little gain from that.

Is it worth it?
If you’re buying new valves anyway........ it doesn’t add that much more to the overall cost of the heads to have the seats & bowls machined for the bigger valves.
Check with the shop you’ll have doing the work for an estimate.

I forgot an important part of the “step 1”........ which is:
determine your budget, and what things will be included within that budget.