Long story short.... I've seen a Nissan Skyline R34 (my dream car) for sale and I'm short £££

I'm a few games (around 13) short of a full collection, if I were to complete the collection, and granted that pretty much every case/disc/insert/manual are excellent condition (around 30 are still sealed) what do you think it'd be worth?

Would it be better to split and sell, or sell as one lot?