Lseries, cheap, perfect fit in a 1200, strong engine and plentiful strong 5spds, also relativelly easy for DIY.
But id say turbo Aseries if conversions/legallity a problem

A15 is easy its a great engine for easy gains as long you dont want something thats going blow away new V8's

A15 with basic head development extractors and good induction and an increase in comp and the smallest Wade cam was the most fun engine package ive ever run in my coupe

I would rate the A15 as the ideal engine.

It can make good power, it fits straight in, they are cheap reliable and easy to work on.

It seems like the possinbilities are endless. The A -series engine and rotaries seem like a popular choice because of their low weight, while high torque motors, which are often more fun on the street, seem to be almost twice as heavy. I am familiar with the obvious pros and cons of the stock engine, rotaries and newer turbo and non turbo fours, but what about those not so often spoken about qualities engines exhibit such as sound, how the engine feels when it pulls, etc.

I'd like to have the ideal engine for a street/performance car, that does occasional autocross and road events. Possibly as a daily driver. But if there is an engine combo that is just too cool than I'd be willing to sacrifice lots of practicality for it.