after market fuel rail and fuel regulater?????
 

whats are some good fuel rails and regulaters?

I'm not sure there are any straight bolt-on rails. Stock rails are good for about anything you can throw at them.

KG makes rails, although the fitment isn't as good as OEM. And there's really no need to get them these days, because you can get up to 2200cc injectors that fit in the stock rail. As for regulators, Aeromotive is fine.

The stock 5/16" fuel line is good for about 300hp before it starts to strain your fuel pump. You can put -6 AN fittings and lines on the stock S4 fuel rail, which are good for about 500hp in series (nearly 1000hp in parallel) before starting to strain the fuel pump.
http://fc3spro.com/TECH/MODS/FUEL/fpr.htm

Aeromotive and SX make excellent fuel components. See the Aeromotive catalog for EFI fuel system component recommendations for a given hp level.
http://aeromotiveinc.com/
http://www.sx-performance.com/

You can get drop-in high-flow injectors from Injector Dynamics:
https://www.rx7club.com/forum/showthread.php?t=920086

Here is the link to aftermarket rails if you still want them for some reason. They are usually made for 3/8" NPT fittings, which are basically the same as the -6 AN fittings that you can put on the stock S4 rails. Most people only use aftermarket rails like this if their stock rails don't allow for fitting a FPR, fitting, or certain types of fuel injectors. For example, FD RX-7 owners may want an aftermarket rail in order to use top-feed injectors rather than the stock side-feed injectors.
http://kgparts.com/index.php?page=kgfuel

I'm not convinced that the stock fuel hose is a restriction for most power levels.

Given that most power levels on this forum are in the 146-250hp range, it isn't. The stock fuel pump and injectors are going to hit a brick wall long before the fuel line starts restricting the flow.

If you are questioning the numbers that I am posting, I am using the simplified guidance from "Four-stroke Performance Tuning" by A. Graham Bell. The Aeromotive catalog has a nice guide that is product-oriented rather than number-oriented. The actual equation is rather complicated, as it depends on the fuel flow volume rate (will vary with the BSFC of each engine), fuel density (specific gravity and temperature), fuel line length, ambient pressure, and the Darcy-Weisbach friction coefficient and Reynolds number of the fuel line. Once you figure all that then you would decide on what is an acceptable pressure restriction for your given application. Even though I normally like crunching the numbers on my own for other factors, in this case I find the simplified guides much easier to deal with. ;)