If you pull the heads, and take them to a high-quality machine shop, with all technical data referencing Lan rover's specs, and ASK what they recommend to obtain maximum performance, you will end-up with the heads you deserve. The cost will range from $800.00 to $2,000.00 for both heads, (considering what you have done), and I'm sure that someone at the shop will agree to install them correctly for a small fee. Over-all, you will get away with spending around $ a grand to do the stock job, non-dealer, if you do some of the prep and finish work yourself. You could buy a set of fresh heads (your heads are taken for a discounted core charge) and you still have to find someone to install, and set them up, and torque them to spec. If you want to take a little time, go to your local high-school auto-shop, and make a deal with the teacher to do the job as a classroom project (these guys are slow, but very careful) and the job might only cost a few hundred bucks, but might take a month. There are a few options for you....let us know what you decide! Did someone run cheap gas in it? Later and best of success to you, Anthony