Frenchie,
All in all your letter is pretty good - I particularly liked how you did the screen shots.
I would hazard to bet that you would do better with a clearer "order section"... as it stands now, your order links of "take action now", "get started", etc... are ok, but a lot of people will want you to hold their hand through the process. Make it as clear and simple as you can, as if for a child...
For this reason, I generally make an ordering section that is VERY CLEAR, listing exactly what will happen when someone orders, with a nice big, clear order button.
Same with the guarantee, it might help to put it in a box to give it a clearer definition and sense of official weight.
Regarding your headline, you can obviously test everything that you have already come up with, and for this, you might want to check out the newest CR% tester software solution that will do this for you well...
www.multitrackgenerator.com
It stands alone right now as far as ease of use towards finding your best CR% (I haven't used it yet, but I was on the conference call that explained it last week)... I am also partners to a tracking software developer, so I know the field well... and this looks very, very interesting.
Michel is very excited about it...
Anyway, back to your headlines... I would add an "If.. then" headline to the group for your tests, something like:
"If You Want To Triple Your PPC Traffic, Save Even 59% On Your Advertising Costs, And Leave Your Competitors Way Behind, Reeling And Rubbing Their Eyes In Stunned Disbelief...
Plug In This Revolutionary "Secret Weapon" PPC Market Research Tool And In Less Than 7 Minutes Unearth And Exploit Deeply Hidden Keywords And Niche Markets Like No Other Tool Available... In Just One Simple Click!"
Could be a double headline, could be a pre-head and headline, and it could be cleaned up further (I just winged it) - but I think it gets your message across clearer, with more umph.
Hope this little bit helps.