I would be interested to hear some peoples' exhaust with the 'economy' solutions. I have heard a lot about the Dynamax Super Turbo as well. Though I am running SuperSprint, it is getting to be 7 years old now, and it will probably need replacing in the next few (though it is still rustless and ni very very good condition). Since I cannot get a new one for $400 anymore, I will need an alternative.
The engine whine has been attributed to the timing chain guides/slippers. It is nothing to be concerned about, it is just the chain whizzing through the plastic/rubber guides.
A neighbor had a 1991 Miata, and it had pretty loud lifter tick. I always though it was gonna blow or something, and the guy barely maintained it, but it held together relatively fine. So, I guess lifter tick is fine...to an extent. If oil detergents do not fix it, you are either severely clogged up with gunk (which IS bad and will cause stuff to wear out a lot faster), or the heads of the lifters are just a little concave from wear and are noisy. If it is the latter, then it does not put you in imminent danger.
Exhaust raspyness. I thought that was somethign that could not be fixed. Well, most of it was from the catalyst to cat-back flange connection. A muffler shop years prior had mesed up the flange and it never sealed right again. My new car has not been butchered like that, and the rasp is 95% gone. The only other place i would think it comes from is cracks in the header welds, or a worn header gasket (at the head or downpipe).
