Hi all, I know this topic is a few weeks old but I thought I would wade in with pennies worth.
I have a 2017 mk3 Fabia Monte Carlo Estate 1.2tsi 110hp.
It is currently dynoed to 195 bhp with 214 lb/ft of tourqe.
To help with your query, the gearbox is stock 6 speed (PRQ, MQ200) with stock clutch and runs full power with no slipping etc. These clutches and boxes are good for 300nm of tourqe as long as you don't abuse them. Like no 6000rpm clutch dumps. There is a difference between fast driving and being a ****.
Spark plugs: NGK Iridium plugs are the go to, platinum plugs get eaten in 40k miles. Please make sure the seats are clean and debris free before fitting new plugs else you will get blow by, evident by a brown powdery coating around the bottom of the coil tube. Be careful when cleaning out muck and debris to ensure it does not fall into the engine. A greasy cloth is good to lift bigger particles out.
Filters, change as usual.
Fuelling : my first round of tuning came before E10 arrived and I ran E5 but once E10 came on the scene I switched to it hoping to save money on fuel, so I had the engine remapped again to run on E10. This was very successful although I lost a couple of horse power and about 10% to 12% of my excellent fuel consumption. However I soon realised that at the end of the day the cost broadly balanced out so when I had my hybrid turbo fitted and stage 3 custom map carried out I went back to E5. This car is now incredible. Producing 194hp, I have decreased my fuel consumption and consistently get 44 mpg at 80 mph on the motorway, similar around town and up 55 mpg on country roads. Top speed is currently out of reach and off the clock.
These engines are near bullet proof as long as you don't abuse them, like all engines. Be a ****... Pay the price. 200hp on the 1.2tsi is not detrimental if you drive properly, I.e, don't thrash the crap out of it, there is no need, it's a light car with lots of go.
Your 140hp will stand you in good stead if you treat it well. No need to worry at all. Just enjoy it for what it is. If you drive long distances, as I do, having the extra power is extremely useful, don't waste it by detuning the engine, embrace its efficiency and effectiveness and enjoy.
A word on brakes: if the car has not had the brakes upgraded, do so at your earliest convenience. I recommend fitting Brembo Max discs all around, or Brembo Sport, take your pick and fit Brembo Extra pads or for the 'Sport' discs fit the matching pads, I can't remember the name, sorry. Also fit a full kit of Braided brake hoses. This will improve braking about 200%. And you should be good to go.
You might want to upgrade the suspension at some point as the Fabias are a bit sloppy when it comes to handling. There are some great systems out there but bare in mind that you get what you pay for. Do not buy cheap. Save and buy quality. I'm running BC Racing Coilovers and love them although they do run a bit hard, but after all they are track orientated. Bilstein or Koni would suit your requirements I think.
Tyres : probably the most important thing, how else is it going to stick to the road? I recommend Michelin Sport Pilot 4. They are excellent in all aspects and will keep you pointing in the right direction in all but extremely cold weather when the tyres just don't get up to temperature. Otherwise you can hang off the edges real well. A lot of the track guys use these as wet weather race tyres... Says it all.
If you want any further advice I'm happy to help. Also very helpful chaps at:
https://www.jbs.co.uk/
All the best.