I'm a pretty tall fellow (6'4"), and, obviously, I have a bit of an issue with my FC's interior space. I can drive the car, but it's pretty cramped.

I had a set of aftermarket rails for my 350Z that lowered the seat and moved it back a bit. Is there anything like that for FCs? I can build a set, but, well. I'm lazy.

 

I don't know of any off the shelf parts, but my buddies race car to be had the seats mounted lower and I could barely see over the steering wheel. So it can be done, but if your lazy then you will just be cramped i guess.

 

I'm 6'4" as well, and I did take a look into getting them when I first got the car, but never came across anything. I don't have any fitment issues though, and decided it wasn't worth the hassles.

Also there really isn't much you can shave off of the stock rails, maybe an inch and a half? Might be enough to get a helmet on in there..

There are rails for 'racing' seats which will probably help you out a bit as well, I do believe that Recaro had a set for their seats, but could be mistaken.

 

Well, I'm lazy, but I can get off my lazy *** and fix things that need to be fixed. I did see that the factory rails didn't leave much room for modification. I may get a cheap eBay seat or something, just for comfort's sake.