you have a 4 banger. Look at the VW 1.9 or 2.0 TDI. I know there are those that think it is a waste and not big enough.
First you need to look at the power ratings of the different VW engines. With some new injectors and a tuner, you can get good HP and torque out of these. Go with a turbo and put a snorkel on it. Fab yourself a cold air intake.
Next go to Acme Adapters. They make the adapter kits to take a front wheel drive VW diesel and turn it sideways to put in a Samari or Tracker. This can be modified for your needs. You can use a Toyota 22R transmission (auto or manual) for the Acme conversion.
I have a friend that is going to convert a flat fender over the winter.
Here is a good mod page for a 1.9 VW diesel.
VW Jetta TDI Specifications