Two of them are Hyper Rev. They're basically chassis specific encyclopedias. Each issue features a dozen plus single page features on various examples, with a couple longer articles (all in Japanese of course). They also showcase many of the various parts currently in production, I'll post some pictures of random pages from one of my RX7 issues.
The other is an Option magazine. They are not vehicle specific and cover a wide range of tuning styles, from the Amuse GT1 to hard core show cars. They used to even cover Japan's street racing scene until the Japanese gov't put a stop to that.
Here are a couple HR pages I took a pic of just now:
https://farm6.staticflickr.com/5610/...1580fd2c_h.jpg
https://farm6.staticflickr.com/5607/...6be90a9d_h.jpg
Amuse's original Touge Monster is easily my favorite modified car ever. Its perfect.