A great (and often overlooked) engine for this type of application is the Ford 23 Duratec MZR. The engine tends to be overlooked because it's a "truck engine".
This 2.3L Duratec is a 16 valve all-aluminum engine that is normally found in the newer Ford Rangers, so it is a North/South setup.
The Duratec MZR is actually Mazda designed and uses a 5-speed Mazda manual trans (or automatic). They have about 150 HP.
Another good choice is a 1.8 Miata engine/trans. They have 140 HP (or more). A recent magazine article (I forget which mag?) showed this swap. Easy to get and if you want to create the illusion of a "Ford" engine, the Ford-badged, twin-cam valve cover of a 1.8 Escort will fit (or at least it sure looks like it will fit...I have both of these cars).