The 87 (I believe) has PCD 5x120 (vs. my 88 with 5x108).
18x8 will fit rear just fine; the front might rub a bit. You also want to check what tires are available for 18x8 - you may not like want you find.
I have 17" Futuras (17x7 and 17x8.5) that fit. To keep OEM offsets, I have a rear adapter of 50mm (30+20mm) to match rear 17x8.5 ET 30. Front did not need an adapter. Tires are 10mm wider than OEM - 205 front, 245 rear.
Note keeping factory offset friendly to bearings; if you insist on aligning with fender lip, you'll need to change adapter accordingly.