Security shouldn't have levels, it should innate!
IE has a horrible track record of security flaws, that install malicious software just by visiting the wrong website. How can you claim that you make it safer. All someone has to do is trick you into going to a bad website, or hack a good website, and do bad things to it.
take a look at the previous versions of IE
Notice all the remote execution flaws, and the 18 unfixed flaws in IE6, you can't make that more secure, unless you work for MS or have some special power you haven't told us about.
take a look at opera, 0 flaws, and firefox still has a few, but notice that any remote execution flaw has been patched, in days or weeek rather than months. MS has let flaws in IE go on for as long as 6 months without even acknowledging them. The United states official computer emergency response team, at one point recomended against using IE6 as a matter of national security to prevent hackers from building botnets.
Think I am wrong, let me know over here, where we can have a sane discussion about it.