[s-cars] Rod knock? metal head gaskets, ARP studs, + CPS?

[Keith Maddock]

S-Heads,

Please excuse some questions here which are probably 75% answerable by
scouring the archives, but I'm in a bit of a involuntary time crunch!

Long story short - On Friday just before departing for a weekend road
trip, 95.5 S6 Avant develops a RPM proportionate (in frequency and
(initially) amplitude) knocking sound.  Tried to limp it to the shop
with last-minute-replacement road-trip vehicle following.  Knocking
got louder so I had to stop and have it towed to the shop.

Just talked to the shop, compression checks out just fine in all 5
cylinders.  Consensus with them is that it sounds like rod knock, they
have narrowed it down to the #2 cylinder.

So, the head is coming off as that is the easiest way to diagnose (as
opposed to what looks like a very $$ process to drop the oil pan).

The small consolidation here is that a timing belt was due anyway, and
@ 120k miles with recently (after 110k mark) installed
Full-RS2/Dahlback setup - no qualms about taking a look at the
headgasket...

Headgasket:  What is the preferred replacement headgasket to make sure
you get the stronger metal peice instead of the paper one.  Are there
any non-OE solutions there?

ARP Studs:  "Might as well while the head's off", any tips on $ and a
good supplier (and even a part number would be awesome)

CPS:  Considering all thats apart, should I pro-actively put a new CPS
in there, and save myself being stranded sometime in the next 3-4
years?

Anything else to consider "while I'm in there" ? 

To add insult to injury, I pull out the Miata this morning @8AM to
head to work (for what was known was going to be a very long day) and
the LF tire is com-f'n-pletely flat.

To make matters worse, the spare was flat too.

Took wheel & spare off, throw in back of roomate's Ranger (he doesnt go
to work until 9:30, bastage), and head to tire shop.  Took 3 stops to
find one that could help with less than 1-3 hour wait.

To make matters worse, the tire wasn't repairable so I had to spring
for a (well 2 so at least one axle matches) new tire @ $200 (pair)
(robbery for 195/60R 14 tires but I **HAD** to get to work ASAP +
get Ranger back).....  
(Which is a shame because those teflon-tires were good fun in that car....)

Thanks in advance for help/advice!
Keith