you could buy a new one stock for about 3400-3800, buy some jets for about 100, and some spare parts for a few hundred. So put that at about 4500, and it should last a season on a bottom end as long as you are nice to it, dont over rev it too hard, and dont run lean. We got 11 outings out of a piston, no blow by whatsoever, we kept it very rich of course, but it wasent raceday so no point. We could have ringged it and lasted a couple more runs. You could probably put a used chassis at like 2500 on a new icc for about 6k. If you want a good long lasting icc, run the fiberglass reeds, keep it rich untill race day, and clean your airbox frequently, or just run a filter on top of the airbox. You should be fine, you will just need to do regular maintanance, piston every 50 liters, bootomend at 230 (TM K9) and a set of fiberglass reeds every season (Carbon reeds every race, 85 for a set). We have had good luck with ours, it just had a water leak and a small hole in the boost port, casting flaw. Barry lewis hasent blown any up or anthing weird, its just when you make it a firebreather with all the pimped out stuff that they cost more then a moto.
for a 7 race CSC, on say a stock TM k9, you could do a piston every 2 races, so like 3 pistons at 85 a piece (whole season) and maybe 2 or 3 rings at 23 a piece. Run the stock fiberglass reeds and you wont have to worry about replacing them the entire season. Get the engine jetted right, they come super rich from the factory, and that will make a huge impact. Alex at DNA down on 285 has a dyno, so that can help ya work with the engine and performance from carb. Probably about a 100 for tubes, mains, piotls, immuslsions, needles, and some spares. Change the oil twice a season or every 5 or so times out if you please, so like 10 bucks there, dexron 3 ATF. Hone your cylinder at the end of the year or when needed.. other then that you should be good, a bottom end over the winter and get all new seals and bearings, so like 500 there, but on a stocker, onl doin CSC and some practice you should be ok for once a year. I have talked to a bunch of guys who just jetted it or threw on a silencer (aftermarket) and ran the whole season fairly cheap. I did the math, for a new engine at 3500, plus expenses is about 4500, add premix another 2 or 300 so lie 4800 (includes the end of the year work)