from a cost standpoint....people have said its the same cost between the I-6 (320) and the v8 (400/420) but you pay just a bit more due to 2 air filters, more spark plugs, and two distrubutor caps
other than the timing chain @ 100K and the wire harness....the V8 is one solid car
do a search with my username....u should find a post called "info on E420" or something like that
great car the 400E/E420 if there was a choice between the E320 and the E420...i'd pick the E420 everytime !!!