Some of the earlier LS/vtec setups were having oil leak problems but really that was about it. If done right an LS/vtec setup can be extremely reliable. As for achieving 12 second slips youll need a little more than a vtec head and some bolt ons especially in an integra. A 2.0L isnt a bad idea. I would have your block resleeved to 84mm add a low compression piston keep your ls head and tranny and add a turbo setup. That would give you tons of torque as it is a heavier car and as long as you keep your boost levels at a fairly reasonable level on the street you shouldnt sacrafice reliability. But hey whos to say what is better than anything else? Good luck with whatever route you go.