if your going to do an s conversion you need to tell insurance and change on logbook, other wise its illegal and voids your insurance and you can get fooked for it, but erm it depends how much you pick an engine up for and labour mostly, but i think an average price for an average 16v with ecu loom, box etc your looking at say 400 for a low mileage one, then theres things that you are goiong to want to change like oil, oilfilter, plugs just a good service, cambelt etc and then labour of doing it, id say around 900ish to say 1100 or 1200, it all depends on labour really mate, i bet you could pick up an engine and all the service parts for less than 500 then its just the labour as its a good couple of days work imo for a garage anyway
erm as for camming 8v again the costs can vary, on what you do, like if you run s1 rallye inlet, what cam you go for as catcams are dearer than say newmans, erm plus the remap costs can vary alot depending on who you go to, and once again the labour
so just say you got cam and pully, and good remap from say chipwizards thats 450 for a remap there and the best there is, your looking at say 700 to 800 depending on the costs of cam and pully, then your going to need to do things like headskim headgasket etc your probs looking at 1k before labour costs, imo your looking at a good 1300 to 1400 to cam a vtr inc labour and parts
from that depending on type of cam and other mods to compliment, you could see 125bhp at very most
and a vts breathered, maybe 135bhp at most, but the cam will give vtr better torque due to the cam so really it could keep up with a vts imo it ouwld be close
either way its not cheap for a good job, imo your best doing it your self as you could half them prices easy well the conversion, caming the 8v would cost 1k if your doing it yourself
or even finding someone you know whos good at this and giving him a few quid, orrrr even better someone off here there are plenty of people who have done both these and im sure will be more than happy to help you for a bit of cash there way and you can trust them more than say a garage lol
sorry its a bit of an essay but thought id explain it a bit better lol
hope this has helped