Welcome! - To answer the title of the post, I think a wrx is right for everybody I can only speak for myself ( 2009 wrx) but I think the general consensus that at least I've gathered on the forums is that if you can afford it, the STi is [I]usually[I] the best option. Don't get me wrong though, a 'simple' wrx is almost too much fun for me sometimes and I love it to pieces, but the STi comes with better bits and pieces from the start. As far as mods go, they are both relatively straight forward with a number of options available for each - You'll find both beefed up wherever you look.
To answer your second question, my old tacoma did 80mph if I tried, but my wrx just gets there much faster now, and I do it with quite a bit bigger smile on my face in the process. I just love the way it drives, the sound it makes, and the enjoyment I get out of it. If you've already driven one, or drive one in the future, I'm sure you'll know what I mean. At the end of the day, you gotta do what makes you happy, but I think a wrx will certainly be able to help you with that