What is the best sleeper tuner platform?

This.

A buddy of mine bought an older turbobrick for $200. He did a turbo swap for $150 and built a home-made boost controller.

Damn thing could probably run a low 12 if you could keep it at WOT for more than 8 seconds without it cutting fuel/timing from sensing knock.

I have driven and owned several race cars (8s range) and that fucking turbobrick was the most unruly and violent car I've ever driven. Zero manners. Raped ape.

First gen honda insight, motor swapped and muffled to hell.

I've heard a lot of food things about ecotec engines, but I'm afraid I don't know much more. In terms of the Saturn Ion Redline, GM sold engine kits and iirc you can get over 240hp with them. I'd imagine you could get more power with some aftermarket parts. Plus a lot of it is interchangeable with the cobalt ss

Any saab with the b234r or b204r, motor way over built and any t3 turbo will bolt right to the factory exhaust manifold.

2jz anyone?

First gen Skoda Superb, and here's why:
These are VW B5 platform cars. Mechanically as good as identical to the B5 Passat, which just so happens to be one of the few generations of Passat to share the majority of its drivetrain with the Audi A4 of the same years.
The Skoda even came in AWD (just like the A4 and Passat), though that's a fairly rare version, and those AWD parts are straight up Audi Quattro bits. This means the entire drivetrain from a B5 S4 or RS4 should bolt right in, and that twin turbo V6 can make pretty good power.
You could even fit one of Audi's 4.2l V8s in there, too. Fairly common swap for B5 platform cars.

And then you can blow people the fuck out at the lights in a fucking Skoda.

cresta/chaser/mkII/verossa

thats exactly what i was thinking
big single turbo 4dr in lame ass white like that would be the awesome.
rhd is the only thing that that sucks about it

We don't have this in 'MURICA

One of these will also house an S4 or RS4 drivetrain. Hell, the AWD bits on the 4motion versions just say "Audi" instead of "VW/Audi".