i had the same concerns as you agent (about service interval)
i personally went for a 68mm pulley with chip & plugs (slstuning). had alot of service done (charger, waterpump, belt, ...) and since then (1.5-2 years) had no major problems! however they claim 140hp, but i don't think it's that much, only with exhaust & manifold, or other mods it would be around that. i m guessing 130 ish
what really made a difference for me were the shorter chargerbellts on the pulley (from roettelle), before that i had slip on the pulley= powerloss), now i dont!