Is it just a plug and play? my 95 del sol tape deck wouldn't fit. thought i'd ask before i went tearing into stuff.

 

It will not be "plug and play" although with a little modding it can be made to work.

The power/speaker plug is diff. so you will need adapters, [avalable at any car audio shop].

Mounting the HU will take a little more effort as the two cars use diff. mounting methods for the HU, the 95 Teg HU uses a "rear mount" mounting system, the pocket is attatched to the HU and the HU and pocket are held in place by two 8mm bolt/machine screws to a brace at the back of the HU, just like this G2... http://www.installdr.com/Insta...9.pdf
Your 99 Civic uses what is called an "ISO" mounting system, both the pocket and HU are mounted into a "rack" using screws into the sides of the HU and pocket, like this... http://www.installdr.com/Insta...5.pdf
DO NOT drill holes into the sides of the Teg HU without checking for clearance on the inside, and make sure the screws you use are not so long that they screw into something they shouldn't. 94