I agree dont really like the idea of wobble bolts just giving the opptions and the 2mm on 112 PCD split between the five studs on a 110 pcd the wobble bolt wouldnt be that much work but like i say i do agree with you
All depends on the quality of the bolts there are some very cheep ones out there that will under heavy cornering mainly start to shift around the 17mm nut seat & become loose, so kits under £25 steer clear of!!
if your a sensable driver & use your car more to cruse rather than hoon around they are a great way to fit other manufactures of wheels but you will need to keep ofsets correct 33-35 any more will req a spacer fitting so front wheels dont hit the strut
& less than 33 will boost wheels out making them rub the arches,
most vauxhalls are 5x110 but all sorts of ofsets threw the range... vec c is 41 req spacers on 17" wheels astras were 39-45 also requiring spacers of 5-10mm which in turn req longer bolts too!! but not too long!! as i found out distroying my rear inboard brake shoes

later vauxhalls from i think 2005 use a differend pcd of i think 114or118?? so check before you i.e bid on ebay just because it says fits vauxhall it may not.. also saab yes are 5x110 but again run approx 41 as its near as damit a vectra c...
Hub converters are a great way again of fitting other pcd fitments but will instantly boost wheels ofset out by 20mm due to having to bolt spacer onto your hub so if fitting a bmw wheel they are already an ofset of 28ish so risk of already rubbing rear arches all a case of measure & trial & error.....