tower has tons of parts still. I order there all the time. if you change to fg arms they are shorter so you'd need firehammer buggy dogbones. I have been swapping and mixing fg and fh parts a lot. I have fg bulkheads on my fh, the angle is just different and the bumper doesn't bolt to the bulklhead itself. fh uses the fg on road front bulkheads and the spacing for the hinge pins is the same as on road as well. the fg mt upper plate that goes to the steering post will be too short to fit the holes but if you find an on road one it'll be fine.. tanks both line up, motor mounts mentioned above, rear bulkheads are the same, shock towers the same, servo trays are interchangeable, not many differences other than wider arms, longer chassis and dif internals. just have to watch for the motor mount alignment (I have to rip 2 of mine apart right now because I mixed up a couple and things are tight on one and too loose on the other lol).. I have 4 sitting here right now with mixed parts on 3. I like the fh mt arms being wider, even on my fg because it gives more stability and fh parts are way cheaper