Got mk4 1.8T and looking to get it remapped soonish

Was looking at stage1 but also seen custom?
Mods so far are:
007p
new hoses
pipercross panel filter/ smooth airbox
sports cat
3"dp
before remap looking at getting:
new tip (heard this can make a difference?)
new cat back (hidden)
I currently run it on normal unleaded cant afford v power

Any ideas what bhp/torque i would see?
Would a custom map be better suited?
Thanks any help appreciated
