Some help figuring out my 86 Carrera's history.

[McLaren-TAG]

I've been the owner of a very solid 86 Carrera coupe for a year now. Lots of work to the car's suspension by the PO (all documented and verified) not a drop of oil leaked in the year of ownership. Documented new Sachs clutch and rebuilt transmission. It has SSI and an early OE muffler and since I've gotten it, I've refreshed the entire shift linkage and from what I've gathers is shifting as good as a 915 can. The car is mechanically in phenomenal shape.

Cosmetically though it's a different story, no rust whatsoever because it apparently was a south west car, but it took a beating from the sun and the entirety of the top panels on the car have the clear coat peeling and it looks like crap.

That's a little bit of background, because I'm trying to piece together some of the history and confirm what I've actually got versus the documentation and the info passed along from the PO through a third party.

Apparently the chassis was a roller, and it was mated to a Euro 3.2 along with a Euro ECU, but the serial numbers don't quite fit the "history" of a Euro engine according to the documentation. So I'd appreciate any thoughts as I'd like to know going forward how to prioritize engine upgrades and maintenance.

Chassis VIN; WP0AB0912GS121752
Engine SN; 64G04132 Type 930/21

According to the engine numbers, I've got a US or German engine with Cat. That's a little vague as now I'm not sure if it is a German engine, with a cat, does it have the higher compression and therefore higher horsepower once the cat was removed at the SSI's installed?

I'm basically trying to find out what return on my investment I'd get going with a SW chip, since that return seems to be much greater on the US spec engines than on the ROW engines.

[E Sully]

US engine, lower compression.

[Joe Bob]

PO stories....trust but verify.