This can seem a little weird I guess... but my car (Opel Astra (J), also branded Vauxhall Astra in at least the UK) is a Delta II platform and as far as I can tell from videos etc. at least the engine compartment and front struts, mounts seem identical to a Gen I Chevy Cruze. (The Vauxhall is IDENTICAL to the Opel, the Chevy might be different in some ways but like said the platform is the same. Same engine also, 1.4 L Gas turbo, 103 KW)

Now the problem is that the front bumper is way too low to the ground for my liking, there are slopes where it inevitably scrapes the ground. Winter is coming and I'm a little worried that it'* going to start working more like a snow scooper instead of a car.

Questions... first of all how can I identify if the previous owner has in fact for some reason installed a "sport" suspension? (*) I've had zero luck trying to find out what is the stock 'regular' strut height or suspension travel supposed to be, or any information like this. It simply is not to be found anywhere.

Secondly, there are lift kits like this https://www.ebay.com/itm/Front-strut...wAAOSwesVbPZtY , available, but I haven't found ANY instructions on how they are installed. I don't have experience doing stuff like that either (only changing wheels... a lot of changing wheels) but I'm not afraid to learn, there are videos showing how the strut can be removed and it looks VERY straightforward.
HOWEVER, where does that spacer go? On top of the strut? Does the coilover need to be disassembled, is a spring press needed as well? (if so, that might prove to be way too infeasible at home). A friend told me he has a place with jacks and tools and who knows what, but apparently he was drunk when I talked to him, or he really does not know what a MacPherson strut is. Or both. No idea, he drives BMW'* (one of them is actually the only 200+ hp car I've ever sat in! 265 hp. Of course that'* nothing for you Yanks jk ). He said you could just "slip that thing in there from the top side" and I couldn't understand what he meant. How would it FIT from the top side, and how would it then properly lift the car from a strongpoint, which is what I think those are intended to do?

So there are kind of 2 things. I would need to find out if my current coilovers aren't some sort of lowered 'sport' variant. If they are, I guess I'd then need to replace them with HEIGHTENED ones. OR, if the car is that low with the 'regular' coilovers, I'd need the 20 mm spacers (or taller coilovers would also work in this case).

The idea would basically be to just get 10-20 mm more clearance (possibly slightly more in the front, there are 30 mm versions of those spacers). Not a LOT anyway, just slightly more clearance so depending, even the current tires would do or I could fit larger ones without bottoming out. 205/60/R16 now, 205/55/R17 could be an alternative, or something in 215 but I don't know if there'* any benefit from the extra width. Especially with the weak engine, I'm also looking to get new, lighter, rims (from experience, they make a world of difference in underpowered cars. Incredible difference).

(*) (There'* a 'FlexRide' adjustable suspension factory option available but I'm quite sure my car doesn't have it. If it did, I was told there would be dedicated suspension setting buttons right on the center dash but they're not there.)

Anyone?

Does the bumper scrape or is it just the air dam?

Do you enter these slopes straight on or at an angle?

Could you post a picture of it from the side? We can tell pretty easily from that.

You could fill the fuel tank all the way then measure the overall height compared to factory specifications.

Speaking of which: What model year is this Astra?

By the looks of that one, it looks like it goes between the spring and the saddle. This would be a bad thing as the car would ride against the far end of the strut'* travel. You need to watch out doing spacers on this kind of car, even one that spaces it between the strut and body. This can put a lot of stress on CV joints. You'll also need an alignment if you do this.

He probably means he could unbolt the strut from the body and slip it in there. I don't thing the product in your link does that. Still, notes above apply.

Picture from the side please.

If it were me, and I were desperate to lift this model car by this small amount and I wanted it to be reliable this way for a long time, I'd lower the engine/suspension subframe and all four struts by the same amount with spacers etc. as needed. This would involve checking for hoses/wires/cables/etc. that wouldn't be long enough, then resolving as needed.

Less than 1% taller, not worth reprogramming, but also not worth doing only to have ice build up inside the (taller) rim more easily.

No benefit to extra width in snow and ice.

This won't really help or hurt in snow, but yes can make a difference in performance, especially if you are coming from steel rims. My suggestion: Get factory alloys from a junkyard as they will be durable and lighter while also being replaceable when the aftermarket rims will have gone out of production.

I bet it doesn't since it has the little engine. A suspension up-option on this car would be surprising.