I went to the Austin F1 race last year and was sitting in a grandstand at the end of a long straight. I took a lot of pictures which can be found at http://www.pbase.com/lebthree/f1_austin
. Most of these are heavily cropped and I pretty much loaded all but the God awful up on pbase so it should give you a good idea of what worked and what didn’t. As I recall, I was using my 70-200 2.8 for most of these. It also appears that I took most of them at f/4. I also used my 1.4 extender on a few. Therefore, your lens selection may work out great.
Depending on your seat, you may find it difficult to take pictures from the grandstand during the race as people will often be standing up at the critical moments. This is especially true at the start. Also, unless you are very high in the stands, you are likely to be shooting through fencing. My better pictures were taken on the practice and qualifying days as there were fewer people and you could move around to various locations. I don’t know what mobility, if any, you will have at the Malaysian GP on practice and qualifying days. As you noted, the main straight may allow you to get pit action during the race which might necessitate a longer lens. However, negotiating it in a large crowd may be a problem.
I would also suggest that you make sure that the venue allows you to bring your camera gear in as many do not allow “professional” camera equipment into the facility. They have such a limitation in Austin, but they did not appear to enforce it too strictly. However, I would hate to show up with a 400/2.8 or 500mm+ without knowing for certain that I could get such a beast in the gate. Each facility may be different and what they say on their web site may not measure up to reality at the gate.
The most important thing to bring is ear protection. The sound is painfully loud and you will suffer hearing damage if you expose yourself to this for any extended period of time. In Austin, the sound is magnified in the main straight as it is a canyon between large grandstands on each side.
Walk around a bit before the race with a good walk around lens. Some of the people attending the race are a spectacle in themselves. The crowds, fences and limitations on movement on race day make photographing the race action very problematic. If you have a press-pass with access to the areas with holes in the fences or scaffolding to shoot from, that is a different matter. For everyone else, my thoughts on race day are to bring what you have, take a few shots and enjoy the experience.