I won't knock t-racks cause I self mastered my first album using it and I thought the results were really really good, if not on the professional side (less than more I think listening back to it).
A lot of plug ins give you kind of nasty limiting and harsh eq-ing, though based on what you've told us about the project you may be able to get away with using t-racks pretty effectively for sparse tracking arrangements, I think it begins to break down and fail on dense and loud rock songs. I still would recommend mastering in the analog realm if at all possible, hit it with a few compressors out of the computer and maybe limit and eq coming in, or eq going out to a few compressors and limit going back in. There's no one right way, if you're intent on DIY (like I am too) then play around a bit, but mastering is frustratingly difficult to get right and you may make a better investment paying someone to get everything up to snuff for you, it may be worth it just for the peace of mind... have fun!