try to switch them with the other pair of the problem is also switched them are gone, if the problem stays on particular cylinder , most probably carbs.
any gsxr gsxf bandit oilboiler coil will fit
ignition cover is the same on all oil coolers, starter clutch cover: 600-750-1052 is the same, and for 1127-1157 it's different with a bigger hub to accommodate the bigger clutch.