My experience has been with the Audi I5 motors running CIS. I've actually been contmplating how to shoe-horn one into an MK1.
Failing that the amusing idea is to hack off the not needed EM port and block it off to allow the use of the k26 or k24 turbo. I also have a couple of 5-cyl CIS dizzys and have also been contemplating that since it will add a substantial amount of fuel as an extra injector, perhaps pressure switched.
Similar to the VW 8V, the 10V I5 is not a cross-flow head and is prone to detonation. The easiest way to get more power is really to do as others have already suggested, especially since you seem to be fairly new to all this. The best bang/buch for an Audi I5 is to go with the 20VT motor instead of the 10VT.
A mild cam will help an 8V as would solid lifters, but then you must adjust them.
And lastly, returning to the start, CIS is VERY reliable. Once you have your zero and basic settings done (DON'T mess with it unless you buy a manual and fully understand things) the final adjustments are very simple. That's my $0.02 and I hope it helps.