Due to the complete variety of answers i have decided... I will download BOTH
Yup, I get paid £5 to cut our grass and I have already downloaded S&P so all I need is 1000 more points to get Waverace 64. So that £5 and another £2 that i alredy had can go towards the 1000 points bought with credit card (£7).
I have both now, and if anyone were to repeat the question, yes Sin & Punishment is slightly better but a bit pricey for what it is.