Caution a frenchie is on board

Well hello everyone, I've done some of my howework so I'll follow the guidelines of ths forum :

[b]Real name:[/b] Romain

[b]Age:[/b] About 31 but it's getting updated every year or so

[b]Location:[/b]France obviously, Magny Cours to be more precise (albeit not right)

[b]Polo owner, if so which? Or looking to get?:[/b] Yes,I have a mk4, kind of as it's a rolling shell for now but more on that later

[b]Previous car history:[/b] Renault R19 1.4i, Nissan 200SX S13 (still have it, not stock...at all), polo GT mk4 (still have it and that's why I came here and pretty much stock),
Honda prelude 4G 2L (almost stock)

[b]Hobbies/interests:[/b]Registered on a forum for a car rolling shell that's almost 20 years old and you're asking ?

[b]Occupation:[/b]Engine bench operator/technician

[b]How did you hear about us?:[/b]It's name begin by a G, end with an E and it's watching us right now.

Well now that we're intimate time to get juicy but a little recap to explain how/why I came here.

Back in 2010 or 2011 I had my S13 which was... well a S13, so fu**** unreliable. Had some trouble with it, a lot actually, and after an other breakdown I decided that I needed a reliable/economical/cheap/readily available car. One of my mate had a polo GT mk4, I don't know how the trim are working on this side on the channel but in France this is the model equipped with the AFH engine. It had around 250 000 km (155 000 miles) at that time, it was an ex riced up car and only had 2 owners since new. My mate was the second one from 110 000 km (68 000 miles) that riced it up, then de-riced it up with a grinder and a crowbar.

Got it relatively cheap (750£), it was equipped with a short air intake and lowering springs.

I had it for my daily drive for two years, put around 12 000 miles on it, changed the gearbox once and when the one I fitted was giving whinings I stopped it and bought an other reliable/economical/cheap/readily available car which was the prelude 4g.

I didn't sold it as I really really enjoyed it, it was (still is) absolutely ugly (blue with flakes in the varnish, tons of rust stopped by some rust converter, rear bumper was white, hood was black with the paint peeling to show the green under it) but the engine was fun, it was (still is) the best braking car I ever had and everyone was mocking me/the car until the first corner. I didn't had place to store it at that time so the mate I bought it from just stored it under a tree at his home. That was early 2012.

Five years later I finally bought a house with a big garage to work comfortably on my cars, and others because the garage is really big and you have much more friends suddenly. So I went back to reclaim my car from the nature that invaded it...

Five years worth of dust, leaves, moist and...rats pee. 

I went with 5 gallons of petrol, a battery, tools, a trailer, some  courage and a bit of luck. With put the battery in, tested that the fuel pump was still running (it was), the petrol coming to the fuel rail was still smelling petrol, oil level was good, water was a little low but high enough for a first start so we cranked it. That son of a bitch started on the first time almost immediately ! Well some lifters noise, the idle going from 500 to 1500 rpm but it started and ran without throttle input.

We moved it to the pressure washer to give it a first clean up, and opened all the doors as the smell inside the cabin was unbearable. Some natural weight reduction has occured but it was still in a pretty good shape (read not much more worse than when I left it here five years ago). We tried to start it again to load it up on the trailer, no luck, apparently no more spark but the car was smelling fuel. No problem, I put my body at work and loaded it with the winch, go it back home, unloaded it and began to work on it.

This is pretty much now and here is what I want to do with the car : a cheap trackday beater. I have the S13 for that, but it is expensive to run and most of my local mates have less powerfull cars (saxo/318 E36/206 etc...) so I need something to have fun competing with them.

The problem is well are because there are more than one :

The AFH is toasted, compression are certainly low, the engine was low on power when I parked the car, still enjoyable but it lost quite a lot of power from the first day I saw/rode in this car. This is not a maintenance problem (new plugs/cables/igniter/coil/lambda etc... I well maintained this block during my ownership).

The gearbox is on its way out...again. And as far as I searched there is no cure/solution.

Wich means that I need to do two rebuilds.

Or I swap the car. This is were some of you may help me. I'm leaning toward an ABF engine but I'm not closed on a 1.8 T20 engine.

The thing is I want it to be reliable, light, easy to maintain, easy to cool, with a broad torque curve. I'm not looking for 200+whp, but a thing with 150whp will be more than enough as my mates are/will be running about the same power. The S13 is already swapped with an RB so I know more or less what it involve but I'm clearly not a VW enthusiast.

So here are my questions (and there are quite many) :

Some of you may have done/rode AFH/ABF/1.8T 20v mk4 and which do you reckon is the best for trackday and B-roads action (handling is more important than outright power) ?

For each engine conversion what is needed exactly in term of engine bracket/subframe fabrication/salvaging from other cars ?

What about driveshafts for the conversions ?

How can I by pass the immobilizer ?

Which coilovers brands do you guys recommend ? Again for track and B-roads, not to just stance the car. Or are sport shocks and lowering springs a better combo for what I intend to do.

The brakes where fantastic with the AFH, but on the road, with low power. On track I'm afraid that I could cook them. I'm still on OEM gear front and rear (brembo disks and I can't remember for the pads), is there any aftermarket performance brake pads, and are these sufficient with some ducting and braking know-how or swapping the brakes from a bigger car is better ? ABS is going in the bin. It never worked anyway and it save some weight and space under the hood.

For those that kept reading until the end thank you, for those whom I get answers to my questions thank you very much.