Lastly, while APAP is certainly worse for the liver than NSAIDs it is not worse for the GI tract where NSAIDs most common adverse reactions include dyspepsia, nausea, ulceration/bleeding and other GI problems. APAP overuse can definitely cause GI side effects but not as frequently or severely as NSAIDs such as ibuprofen.
OP - many people can safely take up to 3.2 grams of ibuprofen daily while others are far more sensitive to side effects such as the aforementioned GI ones. Unless you plan on using large doses for long periods, you should be fine by staying within the prescribing guidelines and/or concomitantly taking antacids (preferably a proton pump inhibitor).
The 800mg/day level for ibuprofen is what is required to be listed on labels of over the counter preparations but don't mistake this as maximum safe levels such as the 4g mark with APAP.