There will be no change to the rights and status of EU nationals living in the UK, nor UK nationals living in the EU, while the UK remains in the EU.
Although there haven’t been any recent terrorist attacks in the Republic of Ireland, attacks can’t be ruled out. See Terrorism
You should carry an acceptable form of photo-identification to travel between the UK and Ireland. See Entry Requirements
Around 3 million British nationals visit Ireland each year. Most visits are trouble free.
New drink driving limits were introduced in 2011. See Road Travel
If you’re abroad and you need emergency help from the UK government, contact the nearest British embassy, consulate or high commission.
Take out comprehensive travel and medical insurance before you travel.