Mailarchives (TI89?)

Hi people,

First, would I like to know, where what I buy a calculator TI-89? (Observation: I live in Brazil, and most of the stores that I found in the USA, they don't send for other countries)

Here in Brazil resellers exist, however the value is an absurdity, about of US$ 270,00, that it is even more expensive than I buy at another country, to pay the transport rate and to pay the 60% of import rate.
Unhappily, that should be the great reason, of the calculators of TI they be not known here in Brazil. The calculators of HP already cost almost the same thing that in the USA, and with that, as example, HP49 ends up being cheaper than a TI89.
I got through a friend in Germany to acquire TI92-Plus (Now I lost the contact with him), but due to your size, I am needing to buy a smaller calculator. I was (or I am still) in the doubt in buying HP49 or TI89.

I would like to know, if the programmers of TI they are really active in the development of new versions of OS, because HP49 was thrown at little time and I already observed that they launched several updatings of the same, with bug fixes and increases in the number of functions.

As I am studying Calculus, I observed that TI fails in the resolution of several integral (and other things), however to HP it didn't fail (in spite of the calculator to be more recent). The one that I would like to know, is been the programmers of TI they are getting right the mistakes (bugs), because I also observed that TI launched updatings, however they didn't fix some bugs and the speed of the resolutions they didn't change. (In spite of to HP to possess a CPU 4MHz and TI89 10MHz, the HP is faster in several resolutions of problems, and they are always improving the acting of the calculations, see the file: http://tifaq.calc.org/ti89vshp49.pdf )

If I find some mistake, where that I should send an e-mail informing the programmers of TI, so that in the future updatings the bugs are corrected?

Does anybody know, if TI shows in some site of Internet the changes of each version of OS, that is, what did they get right, did they get better or did they increase?

In spite of me to have some complaints on the calculator of TI89/92+, I think TI89 is much simpler than HP49 and it possesses ideal conditions of passing in front of to HP, but it will only depend on TI, because TI89/92 possesses a machine with a faster CPU and a larger display, now it is only to improve the OS.
I am also a programmer, I know that is difficult to do something 100% (without problems). And I am also in the hope of obtaining improvements of TI.