My '96 1.4 SS had the foam in when I bought it in 2007 and I replaced later that year and in 2010 without any problems being experienced; the foam was completely intact on both occasions, just a little stained and a bit hardened where it had been compressed by the fixings. I duly went to replace it again in 2013 and was horrified to find it substantially disintegrated and virtually completely blocking the oil pick-up. The "uncharacteristic" oil pressure readings that I had been experiencing - which I had put down to instrument/electrical issues (the water temp also having been erratic) - were thereby graphically explained. The clean-up process was necessarily painstaking and very laborious, with the nagging worry that finer particles were still likely to be in the oil-ways. Needless to say, I did not replace the foam and followed the sump gasket modification detailed elsewhere on this site. I have run the car without foam ever since and have had no apparent problems. However, I must also mention that I have not taken the car on track in recent years. An Apollo tank is also fitted (installed in 2009). A further point to mention is that the engine suffered head gasket failure in 2011. It was not a sudden, catastrophic failure but rather, it seems, a partial failure worsening over an extended period of time. I believe I have read elsewhere on here in the past that other foam disintegration experiences have coincided with HGF. Equally, however, there are others where there has been no apparent hint of HGF. The type of oil used has also been suggested as a factor but, in my case, this will not have applied - it has always been the recommended Comma Motorsport oil. Annual replacement of the foam may be the answer, on the basis that it reduces the period over which the foam could potentially deteriorate and disintegrate. Personally, however, every oil change becoming a sump-off job is too much of a pain in the @ss to contemplate. Having said this, Stephen's (L7 FST) comments are worthy of note and I may think differently if I were to take the car on track days again in the future.