FP2 & FP3 or S3 & S4?

Hi I'm just heading into A2 and one of my courses is further maths where my class are doing S2, FP2 and FP3 (Edexcel) however after looking at both FP2 and FP3 books I've got a feeling I'll struggle.
I've completed S1 and S2 over the summer and I've really started enjoying statistics and want to continue it. Plus I'm applying to do actuarial science at uni which is hugely statistics based.
What advice would anyone give about doing S3 and S4 over the further pure modules? Obviously since my class are doing them I'd have to self teach S3 and S4. Are they as easy to self teach as S1 and S2? I've noticed they're quite short modules so that'll give me time to perfect them and hopefully get 90+ ums in them.

For Further maths you have to do at least 1 from FP2 and FP3. I'd suggest studying those with your class and self teaching either S3 or S4. This way your worst unit will be discarded and your Maths A levels calculated on the best 12 units.

(Can't offer further advice as if it were me I'd pick FP2 and FP3 every time over stats but then I don't like stats.)