Recommendation for '97 Fuel Pump

So I am pretty certain that my check valve is shot on my '97XJ. It instantly looses all pressure after shutdown, but has the normal 49psi while running.

Can anyone recommend a quality pump assembly?

I just replaced the pump in my 97, the check valve in that assembly is simply a washer that 'floats' allows fuel in, but sinks when there is no flow in.
if you can drop the tank and tear into the pump it's not hard to understand how it works. I know my filters were filthy, would be worth new ones if your getting into the tank anyway.

I don't know if I would be better off tearing into the pump or just replacing the whole unit.

Can the filter/regulator be replaced aside from the pump unit?

Do a search on the bmw check valve. A reasonably cost effective cure to the bleed off issue and you don't have to drop the tank

Whatever you do, don't buy an el-cheapo fuel pump assembly. There is some crap floating around out there so beware. You DO get what you pay for in that regard. Go with an OEM style from a reputable manufacturer and you will be fine. A lot of guys replace the entire assembly instead of on a component basis and while maybe not the cheapest route, makes sense in other regards because of the location of the assembly being inside the tank.