can i fit it correctly, i know the dimension is 6.5 but how accurate is it? is it gonna be easy to install myself?

wut dimension are our stock tweeters?

Do u mean tweeters or just the stock 6.5" speakers? Tweeters are usually sized in mm. If you are just replacing your stock speakers you shouldn't have too much of a problem, but if you've never changed out speakers before id take it to a professional. If you're adding tweeters you should just have to take out your head unti and run the speaker wire to it and mount the tweeters on the front of the dash, in the corners.

The MB Quarts can fit in the back but it will take a little modication to either the mounting bracket or the outside rim of the speaker for you to be able to screw it down. If you bring it to someone they will usually make up some type of bracket but you can easily do it yourself. I just switched my speakers for the 3rd time and its not hard at all. It depends on how picky you are when it comes to working on your car. You can either make a full new bracket like I did or just simply take an air grinder and grind down a corner of the bracket so that the speaker will fit in correctly. You have to do this because the rear speakers are in more of a square shape rather than a circle.

i just got through putting 6.5" comps in my 94. i dont know about your car, but mine did not have any stock tweeters, so i mounted them in the sails of my door. as for the 6.5" speaker, i had to make a reduction ring to make it fit perfictly. none of it was very hard, but the hardest of it all was running the wire through the rubber boot.

The stock rear speakers are exactly 6inch or 15cm which is a very rare size.
I know of only JL Audio who make speakers in that size and they weren't cheap last time I looked.
I managed to fit some 15.9cm (about 6 1/4 in) Pioneers with just slight trimming of the brackets. Some pics I did for a 'how to' on another site below...

The yellow shows what needed trimming. Fig 3 shows the spacer ring that had to be took off the old speaker and fixed to the new so that the speaker lies flat against the door panel.