Youre on the right track. Although not sure if your rear deck has holes for components. If not just throw a coax in there. Dls424 probably would work well w your morels. Also consider rainbow sl100 or infinity 42.9i
Ask technic about spacers. He may be able to score you some.
Also technic will sell you connectors with purchase of a harness
FS:Sub Amp - works w/ Technic harness! MRD-M300 - cheap
DON'T BUY FROM RAF555!!!! Promised fix! - strung me along til Paypal dispute period expired!