Hi Dave and welcome,
There are several sellers from various parts of tinternet, some are are worth fitting some not, trouble is there seems to be very little in the way of manufacturers markings to distinguish good from bad wishbones.
Known bad sellers are buypartsbuy for wishbones, going by other members posts, although others items seem reliable, and first line, avoid like the plague for all except filters it seems, certainly in my experience anyway.
The only reliable supplier that we can bolt a cast iron thumbs up to are Lemforder, they make and supply the originals to gm along with numerous other bushed chassis components, although these are in the order of £110 delivered from autovaux they are considerably cheeper than 235 a side from vx for the same part less a gm sticker.
When fitted be sure to tighten the bolts wheels loaded to avoid early failure. But when choosing supplier, also consider the cost of more likely early failure when fitting cheeper parts, your back to square one of they fail, possibly costing a pair of front tyres in ware, remove and fefit another set of wishbones and set up again. Could be a pricey pair of cheep wishbones. Having said that, plenty here have fitted cheeper wb's, just none know tha makers name.
Self level springs, kyb from most factors do the job nicely for 80 to 90 a pair, the sl shocks are only availabe from vx for 150 a pair on trade club, or just fit stock springs to go with the stock shocks, depends if you need or want the levelling option.
Shout if you need any vx parts on trade club as i have a card, or follow the abs link at the bottom of my post for the tc card.
hth