With a New filter and zard pipe you can try the factory arrow race tune (mod the airbox too). Without the cat you're looking at possibly using Indy's tune.
As for ceramic coating, main benefits are reduced external temp of headers, easier cleaning, longevity and more heat going out the end can.
There are different options, ceramic paint or plasma sprayed. The former is the cheapest at about 120 quid from camcoat. The latter I priced up from zircotec, are you sitting down? For their basic black primary coating is approx 280 + shipping. For their performance colour range it's just shy of 400 + shipping
The MOT ain't a problem, bikes dont get emissions tested like a car