Wheel/Tire n00b, need advice b4 I blow my cash

Car in question: 95 Civic LX

I'm going to buy 4 new rims and tires and I've got my eyes on some 16 inch ADR rims.

their specs:
16 x 7, 40 offset, 20lbs, 4x100 bolt pattern

From everything I read these should fit onto my car with no problems right?

now for the n00b questions:

7 inches is wider than stock. Is that too wide? most all of the 16" rims I've seen are about this wide, just don't want them too wide, you know?

How do I know if I need tuner lug nuts?

Checked www.tirerack.com and they said that with 16inch rims I should get 205/45/16 tires. Is this accurate?

Also- If my new wheels weigh more than stock, will I need my speedometer recalibrated?

See I told you they were n00b questions.
Thanks for any/all help!
ripthesystem