Depends what budget you have. If you have decent management then your options are open. Me and a friend have identical bottom ends that were build for a few hundred quid and work well and do what we want. Im using a ZVH 2.1 and a friends is ZT 2.1. Just find a H/g to suit your compression.

The bottom ends are basically this:

Block bored to 86mm
Vauxhall c20XE pistons
Silver top rods machined to 21mm
Pistons drilled ( to allow oil to the pin)
8mm ARP rod bolts

My ZVH got 246bhp and my friends ZT got 299bhp.