Hi there, I'm also working on the Mclaren at this moment, and it's quite normal it takes so long...did 21 parts in about a month.
When your working on your own model, it will go faster cause you already know what to do, and you already have the skills, but 3 to 4 days ?! Nah, that's for the guys that spilled a bottle of superglue over their keyboard and are stuck behind their pc.
happy modeling on the mcLaren !
ps : as for the completeliness, dunno about that, but I learned almost anything from scratch about spline modeling/patching. Never did that before, and now I'm eager to work on some models I didn't know how to do before, so that counts getting towards completeliness :p .