K20 would be the best option I think. Yes it costs more, but for that cost you will have:
- Custom header
- Custom exhaust
- Custom intake
- Hondata ECU
- 6th gear
If you buy a B18C with:
- Good after market header
- Good after market exhaust
- Good intake
- Hondata S300
How big would the difference be then?
B18C will be easily 2000 pound, header 300 for a 98 spec, Hondata S300 400 quid 2nd hand, intake say 100. So that is easily 2800 for a B18C that will then make around 215-220. Yes the K20 will cost much more but will give you 20hp extra easily, 6th gear, broader power band and is easier to get more power out. Apart from the mpg which, is said, pretty good too.
Then there are parts that are brand new while you get the second hand with a B18C swap like engine mounts and shafts, if you calculate new ones on top for the B18 the difference will again become smaller. K20's on themself aren't so expensive, that also goes for the really low mileage ones. And if you choose the right shifter, you'll have a customizable shifter too
So imho it's a great swap and worth it's money, but you have to have the money; a stock B18C swap can be done for 2k + extras like timing belt.
Let's take it further. If you want to get a B18C swap up to the same leven as a K20 swap (and still with less room for extra power, smaller power band and no 6th gear):
- B18C 2000
- New engine mounts 400
- New driveshafts 400
- Good header 300
- Exhaust 400
- Intake 100
- Hondata S300 400 2nd hand
Then, for extra power:
- Good cams 500
- Retainers 150
- Valve springs 150
- Intake 300
- Throttle body 200
That's already about 5k. Then I'd rather spend just that little bit more for a newer, lower mileage engine with a broader powerband, more room to tune, 6th gear and better mpg.
Or am I missing something here?