OK, here's some additional info on the CDR-220. This is all with respect to the standard unit, invisible in the 928.
I am happy to do the mod to change the viewing-angle. It is tricky and was hard to figure out so I need to charge something, but I am not a sponsor here so I don't want to run afoul of posting guidelines. Please send a PM if you are interested.
There are two basic models of the CDR-220, and as far as I can tell they are the same except for some trim details. Here are the two faceplate styles, we wound up with one of each:
The upper faceplate with the all-matte finish is the newer model# 6625, the lower one is an earlier unit (model# 4462). The differences, as far as I can determine, are the part-glossy finish on the earlier faceplate, and the earlier buttons tend to get "chafed" around the edge. (Ours has that issue, hard to see in the pic above-- but Becker Autosound can replace the buttons). Both are nice.
The "CR-220" is a cassette player, be careful. However the faceplates are apparently identical except for the model-designation, so you may find CDR-220's with a CR-220 faceplate. AFAIK that works fine.
Replacement faceplates are readily available on eBay for $100 or less, again in both styles.
Connections: Most used units come without cable or harness but these are readily available (Becker Autosound or SW Stereo, and others). The basic connections are the same as recent Blaupunkt's but check the documentation.
Adaptors are available to connect to a factory amp, our S4 is connected from the CDR-220's preamp-out connector through a Blaupunkt adaptor (left-over from a previous radio) to the factory cable to the factory amp, works fine (except for the 12v power wire, see below).
But realistically, the head-unit has almost as much power as the Blaupunkt factory amp. If the goal is to turn your brains to jelly then you will need a different amp. (We have some available, courtesy the PO). But in that case you wouldn't be reading a thread titled "fighting bling...", either
The GT's CDR-220 is wired direct to the speakers, which are whatever the PO fitted... They sound fine and get drowned out nicely by the howl from Louie's masterful exhaust when the right pedal is depressed at the appropriate moments.
The CDR-220 connects to both the continuous (bus-30) 12-volt connection and the switched (bus-15) connection, as usual. The first keeps the memory alive, the second switches the radio on and off. However, this unit is relatively unique in that it draws its primary power from the continuous 12-volts, and uses the switched 12-volts as a power on/off signal.
So with the key off, you can press the "on" button on the radio and it comes on, for up to an hour. This is terrific for hanging out in ferry lines for example. And when you turn the key on, then the radio comes on, if it was on when the key was last turned off. Pretty slick!
The only problem with that scheme is that the continuous 12-volts (bus-30) wiring for the factory radio is a skinny 1-mm wire that comes from the filter located with the amp, next to the passenger seat. When the head-unit keys the amplifier on, the voltage drop through that skinny wire plus the drop to the amp was enough to turn the radio off again-- resulting in just a "thump, thump" whenever the radio was turned on. The fix was to run a separate 14-ga wire from the amp connection on the CE panel (E-24 for an '88) direct to the continuous +12v radio connection.
Aux cables: The CDR-220 has an aux-in connector in the back, shared with the CD-changer. So you can't have both, but that is not a problem for us. Becker's cable terminates in two female RCA-jacks, from there you need a RCA to mini-plug cable to an iPod or MP3 player. There are also cables available (e.g. PIE) that go direct to a mini-plug, or an iPod connector. And a wired phone connector with mute, if you are so inclined.
Prices: eBay prices seem to run from $200 to $500 depending on condition (from "a bit rough" without code, to fully-refurbished with code). Things to watch for are worn ***** (readily available), worn button-edges on earlier-style units (hard to spot in the usual eBay pic's, but again fixable), and cracks in the bump in the top-center "blinker". (That diamond-shape thing above the display is an anti-theft blinking red light (which can be turned off), it is a thin part of the plastic face and easily cracks if the unit is not well padded for shipment. The faceplate in the GT pic's in the first post is cracked, the white edges of the cracks were darkened with a "Sharpie" felt-pen).
Codes: The CDR-220 requires a 4-digit unlock code whenever the power is disconnected, codes are available from the serial# for a small fee from Becker Autosound and likely other sources. So when buying a unit without code make sure the serial# label is intact. And units on eBay without codes are often attractively priced-- just be sure the serial# is available. A radio without either a code or serial# is a doorstop.
Removal keys: The CDR-220 drops into the factory spot bare-nekked without a DIN-shell, and has latches on either side that grab the bezel. It doesn't actually latch on either of our cars (bezel is too thick), but we got the keys anyway (Beker Autosound again). They are the type that latch in place and allow you to pull the radio out, but we always remove the pass-side console panel for access to the rear.
The rear of the radio is supported by the fuzzy "U" bracket, which fits perfectly. If yours is gone then you will need to replace it, or fit something else to stabilize the back end.
The radio antenna connector is different than the "Motorola" style on the factory radios, you will need an adaptor.
There is some info from the Boxter folks here: http://boxster.wikia.com/wiki/CDR-220_Head_Unit
Becker Autosound's website is here: http://beckerautosound.com/
and their CDR-220 page is here: http://beckerautosound.com/Porsche/9...ette_4362.html
Becker Autosound is a good source for cables, replacement *****, unlock codes, and refurbished units, and can also replace worn buttons on earlier units.
The manual is available here: http://beckerautosound.com/pdf_guides/om43-4462.pdf
Southwest Stereo is also a good source for all this stuff: http://swstereo.com/
Again, please send a PM for info on the viewing-angle mod.