If your main use will be for wheels, then a cordless impact is an expensive luxury. Its real use is for large bolts, such as on suspension, pullers or spring compressors.
The torque rating seems to be a 'multiply it by a wishful thinking amount' as wheelnuts aren't that tight, but many of 200nm rated wrenches struggle with them. Small tools have smaller, low capacity batteries; large ones work better but take up more space. Battery quality is critical, as is motor efficiency. The CP3002 Sealey one I had worked OK for about a year, but its effectiveness tailed off quickly after that. A new battery was almost as much as a new tool, so I used it until it stopped working.
We've been skirting around this for a while, but the best advice is buy a tool that you already have the batteries and charger for. Or, start from scratch, and buy the system that has the most useful tools available to you. I bought into the Ryobi One+ last year as a drill, angle grinder, impact wrench and small vac that share batteries are very handy for small, off the cuff jobs. The grinder works well, when I want to cut/grind a small thing(bolt, short weld, rusty patch etc), but it's not up to a full sill replacement which is when I'll get the corded tool out . I'm tempted by the jigsaw too, as all of my use for such a tool are for small jobs - MDF hammerforms for example.