Customizing an HM Contessa- Advice needed

I've always wanted to customize a piece entirely. I'm going to be using a HM Contessa. Here's a link for the car and it's tech specs.

http://auto.indiamart.com/cars/contessa/index.html

I am interested in doing an overall upgrade. From engine to guage to interior. How upgradable is the car? As in, can you find compatable parts- especially the major ones (like engine, brake+clutch, etc) for this type of car? I am not experienced enough to be making my own parts, I'll have to do with the ready-made parts available. Can you find parts for this type of car easily?

Sorry if I sound amateurish, this is my first shot in such a project. Thanks for the help guys.