Has anyone installed any tweaters in the front corners as i drew circles in phot below?!?!?!

 

You mean the a pillar? It has been done but it's not the greatest idea in terms of imaging. Spacing from driver/passenger is even worse at the pillars than it is in the stock dash location.

Also, if you're going to be running tweeters and 4x6's (what I'm assuming you plan on doing) then you need to high pass the 4x6's so that they won't be playing the same frequencies as your new tweeters.

 

so the extra tweaters would be pointless? I just seen them in my friends truck but i never heard his system

 

If you mount the tweeters there, you may get "more" highs, but you certainly won't have "better" highs. Your imaging will suffer because you'll have a huge near-side bias because the tweeter closest to the listener will be a LOT closer to him than the other tweeter. Plus, you're going to get comb filtering due to the interraction between the directly radiated sound and the sound reflected off the windshield. You're also likely to get some level of standing waves from reflections off the dashboard. In addition, you'll get a comb filtering effect from the interraction between these tweeters and the tweeters in your 4x6s.

Ultimately, what you'll get is sloppy, harsh, undetailed, poorly imaging high frequencies.