I've have 155,000 miles on a 5.0 lx that I just bought, an I was wonder if it is worthwile to invest in a set of quality aftermarket heads, headers, and intake. The engine seems to be in perfet condition and is bone stock, besides oem replacements i.e. water pump, radiator etc. What type of gains in t.q. and h.p. should I expect. Btw, the car does not smoke upon startup or driving in any way. I do have a slight exhaust leak at the headers, so I will probably be doing an entire exhaust replacement.