It can be quite costly to service V4's. The tubes are worth over $200, a cap job is more like $250 and will need to be done soon if it hasn't already, and it's a rather elaborate design so just tracking problems can be time consuming. You should really insist the amp be inspected before buying, ideally agree on a price before inspection unless repairs are too high, and offer to split the inspection cost if you don't buy it. If the seller won't agree to that, don't buy it.
SVP-CL + IPR 1600 + SWR Goliath III 4x10 = bliss