Both of those cars will either need suspension work done or bodywork, or both... same goes for pretty much every used car for sale...
It could be argued that a
cambelt, service, discs/pads and a set of tyres would cost more than a cheap Omega...
Only you can make the decision... if the car is otherwise sound and presentable then it is probably worth spending on. But, if it has accident history causing the issue, then no amount of suspension work will solve anything
Having scrapped a mk2 Granada for £50 of welding and spend £££ keeping a thrice written off plod Omega estate on the road long after most would have given up, the only advice I can give is this:
Any sub £500 car should last until the next MoT... Any sub £1,000 car should be capable of passing the next MoT.
Taking my current Omega as an example... '52 manual 2.2 Gls estate with 102k. Bought for £350 in October, Mot until April. The bodywork is rough, rear arches and tailgate starting, all four doors are dinked and rusting at bottom. So far I have spent £500 on it: new tyres, cambelt, service items, thermostat and rear pads... of which, only the tyres have been fitted (rest is a job for this weekend.) It is showing various codes including both cam and crank sensors and the suspension leaves alot to be desired and will likely cost it the MoT.
I could not spend another penny on it, and save the money instead, or I could collect the parts ready for sorting the suspension in time for the MoT... I haven't actually decided yet, and all the while it gets me to and from work, I won't worry too much. Point is that there is no right or wrong answer.
In your shoes, with that car, I would suggest making sure that the track rods are all free, and take it to a decent alignment place such as WIM or a local independent Porsche specialist (I have had good results from one locally once the revulsion of having an Omega on their ramp wore off
) and get it set up 100% using the previously published settings. If that improves it, then consider renewing components to bring it back to new. If it doesn't, then run it to the MoT and break it as there's clearly something fundamentally wrong with the chassis...