you may get away with not needing one - depends on age and also style of driving - mine was past its best when i had my mapped
IIRC you'll have a different size clutch and flywheel so upgrading would be a bit cheaper (jammy git!)
if you're serious about another car next year then i wouldn't bother sdoing anything (apart from the lights

)and put your cash towards that instead otherwise you're just spending money you'll never see back