attaching を to counters
 

i was wondering if there's a need to attach an を to counters.

which of these would be correct:

1) ごまいをコピーしてください
2) ごまいコピーしてください

Only (2) is correct.

Don't use kana for numbers. Say 5まい.

ok i'l use the number in the future, anyway in the following sentence is に needed:

レポートをすぐに送ります, or is it that modifiers for verbs usually do not need particles?

That に is actually optional but it sounds better if you use it.

ic, thanks for the advice