Hi all im looking for a bit of advice really, i drive a vectra b 2.2 sri and have just started to get the clicking/ticking noise from cold, removed heatshield to find a small crack in the middle of the exhaust manifold, have found another manifold (second hand), but have never fitted one of these before, is there any problems i may come accross? or is it just a case of unbolting the cracked one and bolting the other one back on? Thanks