Hi all was browsing ebay and came across these

http://www.ebay.co.uk/itm/mk3-mk4-rs...item27c4f6dc53

My engine seems sweet but gets abit tappy when warm,was thinking about taking the engine out,see if anything is worn and replace what's needed,but i have no experience taking an engine apart,could my cam and lifters just be worn or is there normally a reason they wear out,theres no knocking at all and out of about 10 cvh'c i've owned 8 have probaly been tappety but want this one to be spot on,car drives great and boost's perfect,idles fine and keeps low temps,what would you do?