the radio from the G1 TL is indeed an internal amp, and the blue plug on the back actually controls tweeters in the dome lamp (harness has four wires). On the G2 Legends, that plug is what controls the steering wheel controls (harness has one wire). For that reason, you will lose the steering controls. It is UNKNOWN just how much power this headunit puts out (even Acura themelves cannot tell you because it was never a selling point therefore never publsized), but it was definitely an improvement in my G1 (looks good too..see pic).
The CD-PEO is a COMMON problem and all TL headunits seem to get it....sometimes a simple CD Player cleaner will work, sometimes it wont....I simply took mine apart, cleaned out all of the old dust and some hair that had gotten into it, and it was 100% better after that. However, sometimes the CD-PEO is a lost cause and you might as well invest in an aftermarket headunit. If you happen to have a headunit that was manufactured in 97 or 98, the CD player is of a better design and will play certain burned CD's whereas the older ones wont play burned CDs at all. Sure the built in single cd player is nice and convenient, but with this HU its is sometimes a gamble and not always worth it....
Heres the pic in my G1.....I cant mentally picture it in the G2 though....