I take the opposite view. .1.Original parts will be the best quality parts your car ever sees, so if they are working, leave them be. 2.All pattern parts and some OEM ones are inferior, and second hand they will have as much wear as your current parts, give or take a little.
If you can prove them to be faulty, then, fair enough, replace them, but I wouldn't go changing things just one the supposition that they might make a difference. At best you'll only waste time and money, worst case you'll end up creating a load of new problems for yourself.
Just MHO.
1.yep.. agreed
2.if you purchase original GM or Opel/VX parts there wont be any problem as they are under warranty..
and if we are talking about a 13+ year old car, I am afraid I disagree..
I think if you can test the part and it's second hand and it's good I dont see a problen but I see where youre both coming from.
as an example though i got a quote (before i found ralfs maf) for a maf fromvauxhall..... £196

theres whole omegas going for less! lol
used and tested is the way forward i reckon