Forum: Rails Engines Design guidance for for Plug-in/Engine based application

Hello,

Is the following app suitable to a Plug-in based app architecture?  I
have been researching this for some time and have not found a clear-cut
perspective to date.  I did receive some generous feedback from a post
on Railsforum suggesting an Engines-based approach, so now I am trying
to further explore that approach.  All thoughts are appreciated.

App outline:

1) 5 module complex work flow system to assist in automobile design:

module 1 - spaceframe,
module 2 - drivetrain,
module 3 - aerodynamics,
module 4 - environmentals,
module 5 - controls

2) Each of these modules are fairly complex and should themselves be
implemented as n-step wizards

3) The modules can either be used in sequence to complete an end-to-end
design project (XYZ Concept Car), or they can be used independently to
assist in the design of a single subsystem or multiple independent
subsystems.  i.e., a project can encompass one or more modules

4) Some modules will produce data that other modules can use to complete
their particular function (for example: controls module needs to know
about drive train and environmentals)

5) A user can have many projects (i.e., a portfolio)


Questions:

1. Is an app like this best suited to an Engines/Plug-in or conventional
app architecture?

2. What's the best way to organize such an application?

1 app?
5 independent Rails applications orchestrated by a sixth app?
1 app with 5 plug-ins?,
...?


Thoughts?  Thx,

Dondi.